A U.S. drone strike on suspected Islamist militants in northwest Pakistan killed 10 people on Thursday, Pakistani intelligence officials said, an attack likely to raise tensions in a standoff with Washington over NATO supply routes to Afghanistan.

The pilotless drone aircraft attacked a compound in a village in North Waziristan, a day after a similar attack killed four suspected militants in the same region.

"The drone fired two missiles at the compound. We believe it was being used by militants," one of the Pakistani officials said.

The United States has been urging Pakistan to mount an offensive in North Waziristan to pursue members of the Haqqani militant network, one of Washington's most feared foes in neighboring Afghanistan.

That looks more unlikely than ever, as a result of a crisis in relations between Washington and Islamabad over a range of issues.

The United States has been pushing Pakistan to re-open supply routes to NATO forces in Afghanistan in difficult talks that show no signs of a breakthrough any time soon.

Pakistan closed the routes, which are seen as vital to the planned withdrawal of most foreign troops from Afghanistan before the end of 2014, in protest against last November's killing of 24 Pakistani soldiers in a NATO air attack along the Afghan border.

U.S. frustrations with Pakistan deepened on Wednesday after Pakistani authorities sentenced a doctor accused of helping the CIA find Osama bin Laden to 33 years in jail on charges of treason.

Attacks by unmanned drone aircraft, which U.S. officials say are highly effective against militants, fuel anti-American sentiment in Pakistan because they are seen as violations of sovereignty that inflict civilian casualties.

After a review of ties with the United States following the killing of the 24 Pakistani soldiers, Pakistan's parliament demanded an end to drone strikes.

Analysts say the CIA could not kill high-value al Qaeda or Taliban militants without cooperation from Pakistani authorities, unless intelligence from informants on the ground used in drone strikes has improved dramatically.(Reuters)