Updated

MIR ALI, Pakistan -- A suspected U.S. drone fired two missiles at a car and a motorcycle in a militant-infested area of northwestern Pakistan on Monday, killing five people in the fourth such attack this week, Pakistani intelligence officials said.

The Obama administration has dramatically increased the number of drone strikes in Pakistan this year in an attempt to kill Taliban militants who regularly launch cross-border attacks against U.S. troops in Afghanistan.

Monday's attack took place in the Khushali area of North Waziristan, part of a semiautonomous tribal region that is almost entirely controlled by militants, the intelligence officials said, speaking on condition of anonymity because they were not authorized to talk to the media. The identities of the people killed were unknown.

A drone strike Sunday on a house in the village of Khaddi, also in North Waziristan, killed nine suspected militants, including a local Taliban commander and two foreigners, the intelligence officials said.

The slain insurgent leader was identified only as Mustafa, and officials said he was linked to Sadiq Noor, a key Taliban figure in North Waziristan.

The nationalities of the foreign fighters were unclear. Pakistan's lawless border region is a magnet for jihadis seeking to fight NATO forces in Afghanistan or train for terrorist attacks.

Unmanned American drones have launched more than 100 missile strikes this year on targets in Pakistan, roughly double the number in all of 2009. There have been 12 such attacks so far in November.

The U.S. refuses to publicly acknowledge the covert CIA strikes, but officials have said privately that they have killed several senior Al Qaeda and Taliban commanders over the years. The program has been criticized as amounting to assassinations that may violate international law.

Almost all of this year's strikes have occurred in North Waziristan, an area in which the U.S. has repeatedly requested Pakistan conduct a military offensive. The Pakistani government has resisted, saying its military is already stretched thin by operations elsewhere.

Many analysts suspect, however, that Pakistan doesn't want to cross Taliban militants with whom it has historical ties and who could be useful allies in Afghanistan after foreign troops withdraw.

The U.S. recently sought to expand the areas in which the drones can target Taliban and Al Qaeda operatives, but Pakistan refused the request because of domestic opposition to the missile strikes, a Pakistani official said over the weekend.

He was responding to a Washington Post report that the U.S. had sought permission to use the drones -- now limited to the northwestern border region -- in areas around Quetta, the capital of the southwestern province of Baluchistan, where Afghan Taliban chief Mullah Mohammad Omar is believed to operate.

An editorial Monday in the Pakistani newspaper Dawn decried the U.S. expansion push.

"A provincial capital bombed by a superpower ally? Unacceptable," the editorial read. "Whenever attention in the West turns to the distantness of the end to the Afghan war, pressure is publicly ratcheted up on Pakistan to 'do more."'

Pakistani officials often criticize the U.S. drone strikes, calling them a violation of the country's sovereignty. But the Pakistani government allows the drones to take off from bases within the country and is widely believed to provide intelligence necessary for the attacks.