Suspected U.S. missiles kill 4 militants in Pakistan

ISLAMABAD (Reuters) - A suspected U.S. drone aircraft fired missiles at house in Pakistan's Waziristani tribal region on Thursday, killing four Islamist militants a day after U.S. commandoes killed 20 people in a cross-border assault.

The latest attack targeted the house of a tribesman, Rehman Wali, in the Mohammad Khel area in North Waziristan tribal region, near the border with Afghanistan, where the militants were hiding.

"Apparently three missiles were fired by the drone," a witness in the area told Reuters on condition of anonymity. Five militants were wounded in the attack.

Military officials were not immediately available for comment and it was not known whether any senior al Qaeda leader was among those killed or wounded.

On Wednesday, U.S. forces carried out a pre-dawn helicopter-borne ground assault on the village of Angor Adda in the nearby South Waziristan tribal region in the first known incursion into Pakistan by U.S.-led troops since the invasion of Afghanistan in 2001.

The United States, a major source of aid to nuclear-armed Pakistan, has not officially commented on the raid, though U.S. officials in Washington said the U.S. commandoes attacked an al Qaeda target in a move that could signal more intense U.S.-efforts to thwart cross-border militant violence.

North and South Waziristan are regarded as major sanctuaries for al Qaeda and Taliban militants.

Anger mounted in Pakistan, a staunch U.S. ally, after Wednesday's attack, with the foreign minister saying Pakistan was determined to defend its territorial integrity.

Twenty people, including women and children were killed, officials said, and a new civilian government, more sensitive to public anger than the previous government, summoned the U.S. ambassador to lodge an angry protest.

Foreign Minister Shah Memood Qureshi said the raid was a shameful violation of rules of engagement agreed with U.S.-led forces in Afghanistan.

"We will not compromise on any violation of our sovereignty," Qureshi told the National Assembly.

"We will defend and ... we have a resolve and we have national consensus in Pakistan to defend our territorial integrity," he said. Both houses of parliament later adopted resolutions condemning the attack.

The United States says al Qaeda and Taliban militants lurk in sanctuaries in northwest Pakistan's ethnic Pashtun tribal areas on the Afghan border, where they orchestrate attacks in Afghanistan and Pakistan and plot violence in the West.

Pakistan has been a close U.S. ally in the unpopular campaign against terrorism and has tens of thousands of troops battling militants but it rules out incursions by foreign troops.

There have, however, been numerous missile strikes on militants in Pakistan, most believed launched by U.S.-operated pilotless drone aircraft.

"FURIOUS"

Analysts said raids like the one on Wednesday will test ties between the allies.

"The people of Pakistan are furious," said former foreign secretary Shamshad Ahmed Khan.

"At a minimum they want an apology ... and an assurance that this kind of operation will not be repeated ... It could have an irreparable effect on long-term relations."

Since the emergence of a civilian-led government after February elections, there has been growing concern that U.S. military operations were becoming more aggressive.

"This is what Pakistan feared," said military affairs analyst Ayesha Siddiqa, adding she expected more U.S. strikes.

While in the past, the government led by former president Pervez Musharraf could virtually ignore public anger, the civilian government led by the widower of assassinated former prime minister Benazir Bhutto will feel pressure.

Asif Ali Zardari, who looks set to become president in an election by legislators on Saturday, is seen as close to the United States but ordinary Pakistanis, many of whom harbour anti-American feelings, will expect him to take a stand.

Zardari, in a commentary published in the Washington Post, repeated his determination to defeat the Taliban insurgency in Pakistan and ensure that Pakistani territory is not used for attacks into Afghanistan. He did not mention the raid.

Commenting on Wednesday's attack, Pakistani military spokesman Major General Athar Abbas earlier said such raids risked forcing people into the arms of the militants and inciting an uprising in the tribal lands.

(Additional reporting by Haji Mujtaba in Miran Shah, and Augustine Anthony in Islamabad, David Brunnstrom in Brussels and David Morgan in Washington, Editing by Bill Tarrant)