The strike, like others in northwest Pakistan, was believed to have targeted the Haqqani Network,which is based in the area and considered by the US to be the greatest threat to Nato forces in eastern Afghanistan.

However, the US government does not acknowledge such missile strikes, which are reportedly run by the Central Intelligence Agency.

Pakistan is a US ally in the war against Taliban and al-Qaeda fighters, but it has voiced resentment over such pilotless drone aircraft attacks.

Islamabad considers remote-controlled attacks, which spark outrage among civilians in the country's tribal regions, a breach to its sovereignty.