A suspected U.S. drone carried out a rare missile strike on an Islamic seminary in Pakistan's Khyber Pakhtunkhwa province, killing six people, including at least two Afghan militants, according to officials. The dead bodies were too burned to be recognized, several news outlets have reported.

Police officer Fareedullah, who only goes by one name, and intelligence officials said the attack took place early Thursday in Hangu district in the northwestern province, the AP noted. It one of the first drone attacks to take place outside Pakistan's remote tribal region, and it could increase tension between Islamabad and Washington, the news outlet said.

Another police officer, Zia Khan, said three students and two teachers were killed in the strike, according to ABC News. Khan said they were all Afghans.

The drone strike took place a day after Pakistan's foreign policy chief, Sartaj Aziz, was quoted as saying that the U.S. had promised not to unleash drone attacks while the government tries to engage the Taliban in peace talks. The U.S. hasn't commented on Aziz's remarks.

Pakistan publicly opposes U.S. drone strikes, noting that the attacks kill too many civilians and violate its sovereignty, according to Reuters. In private, however, officials admit that the government supports the strikes.

The officials spoke on condition of anonymity since they were not authorized to speak with the media. Fareedullah said police have arrived at the attack scene in the Tall area of Hangu.

An intelligence source told Reuters that Sirajuddin Haqqani, the leader of Taliban-linked Haqqani network, was seen at the seminary two days earlier.

Most drone strikes occur in the North Waziristan region where Taliban insurgents are holed up, but are seldom occur in densely populated places such as Khyber Pakhtunkhwa, Reuters pointed out.

A Nov. 1 drone strike in Pakistan, which was denounced by the country's government, killed Pakistani Taliban leader Hakimullah Mehsud in the northwestern stronghold of Miranshah