Tribesmen stand guard at a tribal assembly, South Waziristan.

The region has become a haven for al Qaeda and Taliban militants since 2001 when many fled there from Afghanistan after U.S.-led troops toppled the Taliban following the 9/11 attacks. The militants have used the region to orchestrate their insurgency against the Afghan government and the U.S. and NATO forces supporting it.

Aside from battling the insurgency in the northwest, Pakistan's troops are involved in another conflict in the southwestern province of Baluchistan, a strategically important and resource-rich region neighbouring Afghanistan. Militants in Baluchistan are fighting for more political and economic autonomy for the province.

But analysts say the Taliban and their Pakistani allies are also using Baluchistan as a base for operations and sanctuary. A senior U.S. official said in early 2008 that al Qaeda leader Osama bin Laden was operating from somewhere in Pakistan and that Taliban leader Mullah Omar was directing the insurgency from Quetta in Baluchistan.

The United States, which viewed Pakistan's former president, Pervez Musharraf, as one of its key allies in the war on terror, has given the country billions in military, economic and development aid since 2001.

WAZIRISTAN: CRACKDOWN ON PRO-TALIBAN MILITANTS

This system has survived more or less intact, meaning that tribal elders continue to run their affairs in accordance with their Islamic faith, customs and traditions. Since 2001, the northwestern belt has become a hideout for al Qaeda and pro-Taliban militants. The areas of most concern include South Waziristan, North Waziristan and Bajaur.

From late 2003 to early 2005, the Pakistan army focused on hunting down al Qaeda in South Waziristan, later shifting its attention to North Waziristan. The main battleground is now Bajaur at the northeastern extreme of the tribal belt. It is the smallest of the seven agencies with a population of one million.

Bin Laden - blamed for the 9/11 attacks on U.S. cities - is believed to have passed through North Waziristan during his escape from Afghanistan after the U.S.-led invasion. The government bombing of an alleged militant hideout in the region sparked violent clashes in March 2006. Several hundred militants seized government buildings in the town of Miranshah, leading to confrontations in which more than 120 died. The heavy handed tactics of Musharraf's government - largely a response to external pressure - were widely thought to have backfired, pushing sympathies further towards the Taliban and fundamentalist Islamic beliefs.

PACT WITH TRIBAL LEADERS UNRAVELS

A madrasa (Islamic school) is blown up by security forces in Miranshah, North Waziristan.

In September 2006, Musharraf's government decided to soften its approach, signing a deal with tribal leaders and pro-Taliban forces. Islamabad agreed to hold off military operations, free prisoners and withdraw from checkpoints. In return, militants promised to end attacks on the army, distance themselves from foreign fighters, and stop movement across the Afghan border.

The deal's supporters said it would empower tribal elders to control militants, although critics argued it would create a sanctuary for the Taliban and al Qaeda. In the following months, attacks on U.S.-led troops in eastern Afghanistan trebled, and an October 2006 U.S. congressional report said Taliban activities in the border region had increased.

The deal unravelled in July 2007 amid a surge in violence in northwest Pakistan, following the army's storming of the radical Lal Masjid (Red Mosque) in Islamabad. After a week-long siege, troops killed 75 supporters of hardline clerics at the mosque, many of whom were thought to come from the northwest. North Waziristan militants scrapped the peace deal, arguing that the government had violated it by launching attacks and deploying more troops in the area.

As the pact collapsed, the U.S. president's national security adviser called on Musharraf to take further action against militants in the region, pledging Washington's full support. Violence in North Waziristan and other parts of northwest Pakistan intensified sharply. There was a flare-up in October 2007, when government forces deployed artillery, helicopter gunships and fighter jets in clashes with Islamist tribesmen near the town of Mir Ali. Many were wounded and thousands displaced.

The New York Times reported in July 2007 that the United States planned to pour $750 million in aid into Pakistan's tribal areas over the next five years, as part of a campaign to win over the local population. But there were concerns over how effectively the money could be spent on development in such a lawless and insecure region.

MILITANT VIOLENCE SPREADS

A backlash against the security forces intensified after the July raid on the Lal Masjid mosque, confirming fears that unrest in the tribal areas was spilling over into other regions. Nearly 800 people were killed in militant-related violence in the following four months - many in suicide attacks and bomb blasts. In October, a suicide attack killed 139 people at a rally in Karachi to mark Bhutto's return from eight years of self-imposed exile. The attack was one of the deadliest in Pakistan's history.

Musharraf imposed a state of emergency in Pakistan in November 2007 citing rising militancy as a key reason. He suspended the constitution, sacked most judges and locked up lawyers. Diplomats said his main aim was to stop the Supreme Court ruling that his earlier re-election as president had been invalid on the grounds he was still army chief at the time. Emergency rule was lifted in December.

Bhutto's grieving Pakistan People's Party won elections in February 2008. Musharraf, under threat of impeachment, eventually resigned in August and was replaced by Bhutto's widower Asif Ali Zardari.

Pakistan's new government has committed itself to the U.S.-led campaign against militancy even though it is deeply unpopular.

BAJAUR

Around 2,000 militants are battling about 9,000 soldiers backed by air power. The militants are said to include Afghans, Uzbeks and Arabs as well as Pakistani Taliban. A Pakistani general in Bajaur has described it as a "centre of gravity" for Islamist guerrillas and estimates 65 percent of the militant problem would be eliminated if they were defeated in Bajaur. He described the conflict in Waziristan as more of a "tribal war", whereas the situation in Bajaur has more "international linkages". Pakistani intelligence officers have said al Qaeda second-in-command Ayman al Zawahri is believed to have visited Bajaur in recent years.

There has also been serious fighting in the picturesque Swat Valley in North West Frontier Province to the east of Bajaur. The army has sent in thousands of troops to oust militants in the region who are led by Maulana Fazlullah, a young hardline cleric known for spouting jihad on the radio and riding around on a white horse gathering donations.

The fighting has forced several hundred thousand villagers to flee their homes in Bajaur and the Swat Valley, which had been a popular tourist destination until recently. Civilians have also been killed in army operations. The military has vehemently denied allegations by local people that it is deliberately targetting civilians perceived to be sympathetic to the Taliban or local political groups. For more on this read: Civilians suffer as Pakistan army targets Taliban.

Frustrated by the intensifying Taliban insurgency in Afghanistan, U.S. forces have carried a number of missile strikes in northwest Pakistan and a cross-border commando raid. The assaults have angered the government and strained relations between the allies. Pakistan says U.S. strikes and the civilian casualties they inflict drive people into the arms of the militants.

BALUCHISTAN

A pro-government militiaman during an operation against separatists in Kohlu, Baluchistan.

Saeed Tribal militants in Baluchistan have staged several insurgencies since the mid-20th century to fight for greater political autonomy and control over local mineral resources.

The conflict flared up again in December 2005, following a rocket attack during a visit by Musharraf to the town of Kohlu. This spurred the Pakistani military to launch a major crackdown against nationalist groups in the region. Since then, militants have regularly blown up gas pipelines, rail tracks and power lines, and launched rocket attacks on government buildings and army bases.

The security agencies have responded by targeting hundreds of Baluch dissidents, including political activists, students, doctors, lawyers, journalists and even shopkeepers. In 2006, the Human Rights Commission of Pakistan cited numerous instances of intimidation, arbitrary arrests, torture, disappearances and extrajudicial killings by security forces and intelligence agencies.

Much of the militant violence is thought to be carried out by a group known as the Baluch Liberation Army (BLA), which was set up in the 1970s. The government has listed it as a terrorist organisation. In 2006, the government stopped Baluch nationalist leaders from travelling outside Pakistan and ordered the country's internet service providers to block access to websites containing Baluch nationalist material.

The militants have focused on attacking infrastructure and the army's lines of communication, while trying to draw in other groups to support them against the Punjabi elite. The Pakistani authorities have made allegations that the militants are receiving external support, particularly from India.

Baluchistan was not incorporated into Pakistan until 1948, when Pakistani troops moved in, forcing the Khan of Kalat, the monarch who had ruled the area under the umbrella of the British Empire, to give up hopes of independence. In the mid-1950s, the People's Party, a new nationalist party, was launched by the Prince of Kalat, and in 1972, it joined with the National Awami Party, based in North West Frontier Province, and the Islamist Jamait-ul-Ullema-i-Islam in opposition to the centralising government of President Zulfiqar Ali Bhutto (Benazir Bhutto's father).

Major conflict broke out in 1973 after the intelligence services intercepted a consignment of weapons headed for Baluchistan and Bhutto dismissed the regional government. Thousands of militants fought the national army, which targeted the Baluch tribes' livestock, their key economic asset. The insurgency dragged on until 1977, when Bhutto was overthrown and the military regime of General Zia ul-Haq arrived at a political settlement with some Baluch leaders. Around 9,000 people died in the violence.

DEVELOPMENT AND POLITICAL GRIEVANCES

Development has fuelled local frustration for two key reasons. Firstly, Baluchs feel their province is being increasingly monopolised by non-indigenous migrants attracted by its economic opportunities. Secondly, there's a widespread perception that the province does not receive a fair share of benefits from the exploitation of its natural resources. Baluch nationalists say natural gas generates $1.4 billion a year, but Islamabad gives the province only $116 million in royalties.

One major infrastructure project targeted by Baluch militants is the construction of a strategically important port at Gwadar on Pakistan's Arabian Sea coast near the mouth of the Persian Gulf. Work began on the deep-sea port and naval base in 2002, with the majority of funding coming from China. The port facilities and its workers have been targeted in sporadic attacks since 2004 when several Chinese engineers were killed.

Besides calling for a larger dividend from development projects and the exploitation of natural resources, Baluch militants want more control over their administrative affairs. Analysts say local people have few political channels through which to voice their grievances and demands.

In March 2006, the provincial assembly voted to form a bipartisan panel to try to make peace between the authorities and warring tribal leaders, but this has not yielded significant results. Relations between Baluch nationalists and Islamabad soured further after veteran rebel leader Nawab Akbar Khan Bugti was killed in a battle with government troops in August 2006. The former respected provincial governor, who had joined up with rebels in the mountains earlier that year, died in an assault on his cave hideout - although the government denied targeting him. Several people were killed in violent street protests and bomb blasts following Bugti's death.

In September 2006, the heads of over 80 Baluch tribes met at a tribal jirga (council), and called for an end to military operations in the province, dubbing them "state terrorism". Brussels-based think tank International Crisis Group said in an October 2007 report that the government's approach to the conflict was alienating the province even further, causing young activists to lose faith in the political process and turn to armed resistance as a way of securing their rights. It also pointed out that the Afghan Taliban and their allies in Pakistan are using Baluchistan as an operating base and sanctuary, and are recruiting from religious schools run by the Pashtun Islamist party JUI-F.

DISPLACEMENT

Residents prepare to move to a safer place after an army crackdown in Baluchistan.

Saeed In both northwest and southwest Pakistan, tens of thousands of citizens have fled violence, although in some cases the displacement has been temporary. Calculating the numbers is difficult, due to a lack of access and little political will to acknowledge the problem.

The U.N. refugee agency UNHCR reported in October 2008 that some 190,000 people had been displaced from Bajaur since fighting started in August. Most were sheltering in North West Frontier Province but some had fled into eastern Afghanistan. The UNHCR said it could not access most of these areas for security reasons, and relied on government estimates. The former Afghan refugee villages of Katcha Gari and Jalozai (in or near Peshawar) are being adapted to cater for some of the displaced.

Waziristan has also seen growing levels of displacement. In October 2007, the Human Rights Commission of Pakistan said 80,000 people were uprooted by the fighting around Mir Ali.

International aid agencies are trying to boost their development activities in northwest Pakistan as well as complete recovery work after the 2005 earthquake that hit Kashmir and North West Frontier Province. The tribal areas, in particular, have suffered from poor literacy, scarce development funding and the fallout from the instability in Afghanistan. But the operating environment is difficult. Aid agency facilities have been attacked from time to time, forcing them to suspend work.

Aid agencies in Baluchistan include the UNHCR, which mainly supports Afghan refugees in the province, and the World Food Programme. But humanitarian and development workers have come up against bureaucratic hurdles when trying to help the local population.

In December 2006, the Christian Science Monitor reported that the government had withheld approval for relief distributions in Baluchistan, despite a U.N. survey saying more than a quarter of children under five were acutely malnourished.

"The official logic is that they can't guarantee safety for the internationals, or even for local aid groups," Samina Ahmed, head of the Crisis Group office in Islamabad, told the Monitor. "The unofficial logic, I suspect, is basically neglect more than anything."

In early 2007, the United Nations launched an operation to help improve the nutrition of thousands of women and children in the province. In June and July that year, Baluchistan, along with Sindh province, was hit by severe flooding that destroyed homes, crops and roads, and temporarily displaced over 2.5 million people. There was criticism of the humanitarian response to this disaster - with aid agencies saying their ability to provide relief was hampered by the government's hesitation in requesting international help.