Two missiles fired by suspected US drones are believed to have killed four anti-government fighters in northwest Pakistan, intelligence officials say.

"The attack happened at around 10.30pm (1730GMT) near Bannu and we have reports that four militants, including two Arabs and two Pakistanis, were killed," one official said on Sunday.

The house in the Jani Khel village near Bannu belonged to a fighter, the AFP news agency reported.

Bannu is a town at the gateway to the tribal region of North Waziristan, a known haven for Taliban and al-Qaeda fighters.

Though Pakistani authorities routinely condemn US drone attacks, saying they are an assault on Pakistan's sovereignty, US missiles often target the fighters in the tribal regions bordering Afghanistan.