Pakistani authorities on Monday opened talks to try to resolve a stand-off with Islamist militants who were holding several security personnel hostage after seizing control of a counter-terrorism facility in the country’s northwest a day earlier.

Security forces have surrounded the highly fortified military cantonment that houses the interrogation centre in the town of Bannu, where around 20 fighters from Tehreek-e-Taliban Pakistan (TTP) - an umbrella group of Islamist and sectarian groups - are holed up.

According to a provincial government spokesman, the militants were demanding safe passage to Afghanistan.

”We are in negotiations with the central leaders of the Pakistani Taliban in Afghanistan,” Mohammad Ali Saif, a spokesman for Khyber Pakhtunkhwa provincial government, said.

He said the authorities were yet to receive a response from the Pakistani Taliban, adding that relatives of the militants and area tribal elders had also been involved in initiating talks with the Islamists inside the facility.

At least one counter-terrorism official was killed by the militants, who according to authorities had snatched weapons off their guards while under interrogation.

Several significant TTP members were present at the centre, Saif said.

He did not say how many security personnel were being held hostage. An intelligence officer told Reuters, however, that there were six hostages - four from the military and two from counter-terrorism.

Stepped up attacks

The TTP, which has stepped up attacks since it announced ending an Afghan Taliban brokered ceasefire with the government last month, has long been using the violence in a bid to take over the country and enforce its own harsh brand of Islam.

The hostage situation came a day after the TTP claimed the killings of four policemen in a nearby district.

The militants in control of the interrogation facility had demanded a safe passage to Afghanistan, a TTP statement sent to a Reuters reporter said. It added the TTP had also conveyed the demand to Pakistani authorities, but hadn’t heard back any ”positive” response.

Bannu district sits just outside North Waziristan, a lawless tribal region bordering Afghanistan that has long been a safe haven for militants.

Pakistan’s military has conducted several offensives in the tribal regions since 2009, the time when the area was in full control of the local and foreign Islamist militants.

The operations forced the militants and their leadership to run into neighbouring Afghan districts where Islamabad says they set up training centres to plan and launch attacks inside Pakistan, a charge Kabul denies.