MATANI, Pakistan - Tribal militias allied with the government helped block a Taliban advance in this corner of northwest Pakistan close to the Afghan border, but their success has come at a price: the empowerment of untrained, unaccountable private armies that could yet emerge as a threat of their own.

Tensions are emerging between authorities and the dozens of militias that they helped to create predominantly in and near the northwest tribal regions. Operating from fortress-like compounds with anti-aircraft guns on the roofs, the militiamen have made it clear that the state now owes them for their sacrifices. They show photos on their cell phones of Taliban they killed and point to the scrubland outside, with graves of relatives who died in the fight.

The leader of the largest militia near the town of Matani, a wealthy landowner named Dilawar Khan, warns that he will stop cooperating with police unless he gets more money and weapons from authorities. Speaking to The Associated Press, he adds what could be a veiled threat to join the militants.

"Time and time again, the Taliban have contacted us, urging us to change sides," he said.

Another local militia commander is locked in a dispute with local police, who recently raided his compound and accused him of stealing and overstepping his authority.

The experience in the Matani area - 12 miles from Peshawar, the largest city in Pakistan's northwest - shows the advantages of using proxies to counter al-Qaida and the Taliban, but also the pitfalls. In Iraq, similar forces were credited with creating a turning point in the war, when Sunni tribes rose up against al-Qaida and other Sunni insurgent groups. Many of those Iraqi Sunnis, however, now feel they are being marginalized by the Shiite leadership.

In Afghanistan, the United States is backing the creation of militias, dubbed local village defense forces, to fight the Taliban. The Afghan government is less keen, having seen the damage that warlords with private armies did to the country in the 1990s.

Pakistan's own past shows the hazards of proxies. A large part of the insurgency tearing at the heart of Pakistan today is made up of armed militant groups that the government trained and funded to fight wars in Afghanistan and against Indian forces in Kashmir, as well Islamist extremists they long tolerated to keep control in places like Pakistan's Swat Valley.

"Every time the state delegates its authority by parceling it out to non-state actors, it ultimately backfires," said Ail Dana Haas, a researcher for Human Rights Watch. "The arming of militias in the medium- to long-term always leads to further lawlessness. The militias will seek to maximize their own power, and they will do so at the cost of the state."

Pakistani support for militias, known as lashkars, is less widespread and organized than in Iraq.

Most operate in the tribal regions close to Afghanistan, where the raising of private armies has a history going back to British colonial times. The army and political authorities dole out money and arms to tribal leaders so their fighters hold areas retaken by the military. Militants have ruthlessly targeted the lashkars this year with suicide bombings aimed at their meetings with authorities.

The northwest region is also where the al-Qaida's top leaders are thought to be hiding and is increasingly being targeted by U.S. missile strikes from drone aircraft, particularly the North Waziristan tribal region southwest of Peshawar.

Six suspected U.S. missiles struck two vehicles in the Shera Tala village of North Waziristan on Monday, killing 18 alleged militants, Pakistani intelligence officials said.