An American drone has fired a volley of missiles into a house close to the Afghan border, killing up to nine suspected militants, according to Pakistani officials.

Up to eight missiles were fired at a house in the Dra Nishtar area of North Waziristan early on Saturday, Pakistani intelligence officials said on condition of anonymity.

North Waziristan is considered a training ground for Islamist militants from many parts of the world. American regards it as a command and control centre for insurgents fighting US troops in neighbouring Afghanistan. The identities and affiliations of those killed on Saturday were not immediately known.

The strike is the second American drone operation in Pakistan in a week and comes as the US tries to rebuild its relationship with the government in Islamabad, which in November blocked the passage of US and Nato war supplies to neighbouring Afghanistan. Tensions reached new heights when Nato aircraft bombed and killed Pakistani soldiers at a border post.

The Pakistani parliament has called for an end to the drone strikes, which many in the country regard as an unacceptable violation of sovereignty. There have been significantly fewer strikes this year.

But America is unwilling to stop completely because the use of drones has weakened al-Qaida and associated groups in Pakistan's tribal regions, large parts of which are not under the control of the Pakistani state. In the past Pakistan's intelligence agency has co-operated with the attacks but the government has not publicly acknowledged this.

Civilians have also been killed in the drone attacks but the United States doesn't publicly investigate or apologise for these mistakes.