MIR ALI, Pakistan -- Suspected U.S. missiles destroyed a moving vehicle near Pakistan's border with Afghanistan on Friday, killing four alleged militants inside it, Pakistani intelligence officials said.
The attack by unmanned drones is the second in a week to hit North Waziristan as the U.S. intensifies its search-and-destroy missions in the strongholds of Taliban and al-Qaida-linked fighters who plot attacks on NATO troops across the border in Afghanistan.
The aircraft fired two missiles at the vehicle Friday afternoon near Marsi Khel village, according to two Pakistani intelligence officials.
The identity of those killed was not immediately known but they were said to be militants, the officials said. They spoke on condition of anonymity because they were not authorized to release the information.
More than 100 American drone strikes have killed targets inside Pakistan so far this year, a major surge over previous years. Nearly all this year's attacks have hit North Waziristan, where Muslim extremists run a virtual mini-state outside the Pakistani government's control.
The drone strikes to kill high-ranking militants is rarely officially acknowledged by Washington. The program, which U.S. officials say has killed hundreds of insurgents, has been condemned by critics who say it may constitute illegal assassinations and violate international law.
Foreign jihadists are known to operate in Marsi Khel area, and local tribesmen also say that homegrown militants, including fighters loyal to Pakistani Taliban leader Hakimullah Mehsud, have also moved into the region recently, having been driven out of their strongholds in nearby South Waziristan by a Pakistani army offensive.
Pakistan's U.S.-allied government officially denounces the missile attacks as a violation of the country's sovereignty that threatens to further alienate the population against the army and central authorities. It has asked Washington to transfer the technology to Islamabad so that the Pakistani army could launch such strikes on its own.
American authorities want Pakistan's military to launch an offensive in North Waziristan, but Islamabad has resisted, saying its military is already stretched too thin fighting the Taliban and other Muslim extremists in South Waziristan and elsewhere in the northwest.