Pakistan: Islamist militants seized a counter-terrorism centre in the northwestern Pakistani area of Bannu on Sunday and took hostages to negotiate with government authorities, officials said.

"It's not clear if the terrorists attacked from outside, or if they snatched the ammunition from staff inside" while being interrogated following their arrest, Bannu police spokesman Muhammad Naseeb told Reuters.

He said the compound had been surrounded by security forces. Two other officials, speaking on condition of anonymity, said the militants were looking to negotiate for safe passage to neighbouring Afghanistan, ruled by the hardline Islamist Taliban.

One said about 15 militants took control of the centre after overpowering interrogators inside, grabbing their weapons and taking five or six of them hostage. The affiliation of the militants was not immediately known.

Pakistan has been fighting an insurgency by the Tehreek-e-Taliban Pakistan. The TTP associates itself with Afghanistan's Taliban, which had been trying to broker talks between the Pakistani government and the TTP.

A spokesman for the TTP did not immediately confirm or deny a link with the militants in the compound.