Eight suspected militants were killed in a U.S. drone attack Saturday in northwest Pakistan, intelligence officials said.
A Pakistani security official on condition of anonymity told NBC News the drone had fired four missiles and struck a compound in the forest-covered Dre Nishtar area of Shawal valley, a remote part of North Waziristan.
"Shawal is an area where militants from different countries had gathered and set up their sanctuaries," the official said.
He said mostly tribal militants, Punjabi Taliban, Afghans, Arabs, and Chechen and Uzbek militants have training camps in the area and often suffer losses in the drone strikes.
The strike Saturday was the second American drone operation in Pakistan this week.
Pakistan: Attacks are illegal
Pakistan's government of Pakistan condemned the attack in the strongest terms, NBC News reported.
"Pakistan has consistently maintained that these illegal attacks are a violation of its sovereignty and territorial integrity, and are in contravention of international law" a Pakistan Foreign Office spokesman said in a statement.
"It is our considered view that the strategic disadvantages of such attacks far outweigh their tactical advantages, and are therefore, totally counterproductive," he added.
Last month, a U.S. drone strike killed four suspected militants in Pakistan's North Waziristan tribal region, despite the recent demand by a Pakistani parliamentary committee that such operations end.
The unmanned aircraft can be remotely piloted from hundreds or thousands of miles away.
The U.S. campaign of drone strikes to kill militants in other countries is legal under international law, President Barack Obama's counterterrorism adviser, John Brennan, said last week.
Brennan cited legal opinions from the administration, the U.S. Constitution and the Authorization for Use of Military Force passed by Congress after the Sept. 11, 2001, attacks.
"As a matter of international law, the United States is in an armed conflict with al Qaida, the Taliban, and associated forces, in response to the 9/11 attacks, and we may also use force consistent with our inherent right of national self-defense," Brennan said.
"There is nothing in international law that bans the use of remotely piloted aircraft for this purpose or that prohibits us from using lethal force against our enemies outside of an active battlefield, at least when the country involved consents or is unable or unwilling to take action against the threat," he said.
Pakistan closed its Afghan border crossings to NATO supplies last November in retaliation for American airstrikes that accidentally killed 24 Pakistani soldiers. The government also kicked the U.S. out of a base used by American drones.
This article includes reporting from Reuters and The Associated Press.
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