A suspected US drone has fired on an Islamic seminary in Pakistan's northwestern region of Khyber Pakhtunkhwa killing at least five people, police said.

Pakistan publicly opposes US drone strikes, saying they kill too many civilians and violate its sovereignty, although in private officials admit the government broadly supports them.

Police said the unmanned aircraft fired at least three rockets at the seminary in the Hangu district, killing two teachers and three students early this morning.

An intelligence source said Sirajuddin Haqqani, the leader of Taliban-linked Haqqani network, was spotted at the seminary two days earlier.

Most drone strikes occur in the North Waziristan region where Taliban insurgents are holed up, and are rare in densely populated places such as Khyber Pakhtunkhwa.

The attack took place a day after Pakistan's foreign policy chief Sartaj Aziz was quoted as saying that the US had promised not to conduct drone strikes while the government tries to engage the Taliban in peace talks.

The US has not commented on Mr Aziz's remarks.

A previous drone strike in Pakistan on 1 November killed Pakistani Taliban leader Hakimullah Mehsud in the militant stronghold of Miranshah in northwest Pakistan, in an attack denounced by Pakistan.

Militants often visit seminaries to consult their spiritual leaders as well as to recruit new fighters.