Updated

MIR ALI, Pakistan -- The targets of a suspected U.S. missile strike in Pakistan's northwestern militant strongholds appeared to have survived Sunday by quickly abandoning their vehicle after an unmanned aircraft missed its first shot, local officials said.

It was one of the few reports of anyone surviving one of the escalating barrage of missiles fired by remotely piloted aircraft, which have become a key weapon in the wider U.S.-led war against Islamist militants in Afghanistan.

Local Pakistani television initially reported four people killed in the latest American attack in North Waziristan, where Taliban and al-Qaida-allied fighters control safe havens outside the central government's control.

However, two Pakistani intelligence officials who investigated told The Associated Press that no bodies were found and all their sources indicated the occupants of the car survived the attack near Hassan Khel village.

They said an American drone fired one of its missiles but missed the speeding vehicle, and its occupants quickly bailed out before the second missile hit and destroyed it. The officials spoke on condition of anonymity because they were not authorized to speak on the record.

Sunday's missile strike was the 13th this month. The U.S. has sharply ramped up its unacknowledged search-and-destroy program, launching more than 110 this year in hopes of killing militant leaders who run terrorist training camps and plot attacks on American and NATO troops across the border in Afghanistan.

The missiles appear to have been increasingly targeting moving vehicles -- five of the six strikes in the past two weeks hit cars or trucks -- which shows off the drones' usually precise aim.
Pakistan officially condemns the missile strikes as a violation of its sovereignty and critics say amount to an assassination campaign that may be against international law. However, the U.S.-allied government in Islamabad tacitly allows the American aircraft to operate on its territory.

Washington has pressured Pakistan to launch a military offensive in North Waziristan to bring the border region under control. But the army has said its forces are stretched thin fighting the Taliban in other areas of the northwest.

Pakistan also turned down a U.S. request last month to expand the American aerial surveillance areas from the northwestern tribal regions to include the southwestern city of Quetta, where Taliban leader Mullah Mohammed Omar and other top Afghan Taliban leadership are reported to live.