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

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 neighbouring 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 anytime 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.

US 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.