Recent clashes between ethnic militants and security forces in southwestern Balochistan Province poses a new challenge to Pakistan's central government, which is already engaged in battles with Al Qaeda and its tribal supporters along the country's northwest frontier with Afghanistan.
Demanding social, political, and economic rights, Baloch militants have been targeting troops and government installations with rockets and explosives. Last year some 30 security personnel were killed, along with three Chinese engineers.
The conflict deepened this month when militants hit the Sui gas plant, which provides natural gas to the country. The attack killed four guards and suspended gas supplies. On Monday, two bombs went off in the province, injuring four people.
A resurgence of ethnic nationalism is a reminder of the fragility of this close US ally and nuclear power. Pakistan became a separate Muslim state after the British quit the Indian subcontinent in 1947. But the bonds of religion have not eliminated ethnic tensions in the country, which has seen violent separatist movements among its Pashtuns, Balochs, and Sindhis - as well as a successful bid by Bengalis to carve out an independent Bangladesh.
Separatist struggles peaked in the 1970's, but the war on terror has put new pressure on Islamabad to override local autonomy arrangements that have kept the peace. The violent pushback by Pashtun and Baloch tribesmen could limit how far Islamabad can go to help the US in the fight against Al Qaeda.
"The situation in Balochistan is [trouble] for Musharraf. If he launches a military action, then it could inflame the situation and may hurt his efforts to fight against Al Qaeda militants along the borders," says Mohammad Riaz, an analyst in Peshawar. "He cannot afford to open another front; he needs to solve the issue politically."
Balochistan spreads over 135,000 square miles but is home to only 6 million people. It borders Iran and Afghanistan, giving the territory strategic importance to both Pakistan and the US, which has been turning up the heat on Iran.
"[Balochistan] is ideally located for any military incursion into Iran," says analyst Shamim Akhtar. But, "if America plans to launch an attack on Iran, it will ignite the situation and could create a new wave of problems for Musharraf."
In the 1980s, Balochistan served as a key staging area for the anti-Soviet resistance in Afghanistan. Mullahs made inroads into remote areas, established madrassahs, and later helped the rise of the Taliban movement.
Islamabad aided the Islamization of Balochistan partly to quell Baloch separatism as the mullahs politically marginalized the nationalists. Today, the provincial government is still ruled by a coalition of hard-line religious parties that allegedly still support the Taliban - forcing the Army to beef up its presence there now.
"There are still imprints of Talibanization" in Balochistan, says Shamim Akhtar, a researcher at Karachi University. "It is important for [the government] to counter any terror threat from Islamic militants."
Economic woes and plans for new troop cantonments have stirred a dormant movement. In the 1970's, nationalists fought for "Greater Balochistan" to unite Balochs living in Pakistan, Iran, and Afghanistan.
These days, Baloch nationalists want more control over resources and more jobs. The Sui gas plant has been a sore point, as Balochistan was the last area to get the gas being sent across the country. Nationalists now want a greater share of revenues.
Another target for militants is the coastal city of Gwadar, where a major port is under construction. Officials say it will provide opportunities to locals, but nationalists say such jobs have in the past gone to outsiders, particularly Punjabis.
In response to the violence, thousands of Pakistani troops have been deployed in the province. Musharraf has threatened militants with the use of force unless order is restored.
Most nationalist leaders distance themselves from the militants, but share their views. "We do not demand Greater Balochistan, but we want to see the oppressed Balochs prosper," says Sanaullah Baloch, a senior political leader.
Local sources say the militants are mostly young men who operate in small groups and total in the hundreds. The militants also enjoy the support of Baloch tribal chiefs, or sardars, who have private forces.
Pakistani officials say that nationalist leaders are carrying out a "narrow-minded" agenda and say the sardars are sacrificing development in order to maintain their own control.
Balochistan is the least developed area in the country. Islamabad has recently approved an economic package of $50 million, with a promise of providing more jobs and development projects.