Pakistan's security forces ended a three-day standoff with Taliban militants who had taken over a counter-terrorism centre in Bannu district in the northwestern Khyber Pakhtunkhwa province.
The militants, who were detainees at the centre, seized the facility, taking hostages and triggering a two-day siege.
After the standoff, Pakistan's military stormed the centre and killed all the militants.
While Reuters reports on 25 militants killed, the BBC News reports on 33 and The Independent initially suggests it to be at least 30.
Two army commandos and a security official kept hostage by the militants also died during the operation.
The army reported that seven of the militants surrendered, and a further three who tried to escape were arrested.
Pakistani Taliban militants who seized hostages and took over a counter-terrorism centre were killed when security forces stormed the facility after a three-day long tense standoff in northwestern Khyber Pakhtunkhwa province.
The number of militants killed varies with Reuters reporting 25, BBC News initially reporting 33 or more, and The Independent initially at 30.
Two soldiers and a security official kept hostage by the militants were reportedly killed during the exchange.
Reports from Reuters and BBC News suggest that a total of around 35 militants had been detained at the facility on suspicion of terrorism for years.
Following the raid, Prime Minister Shehbaz Sharif mourns the loss of security personnel and acknowledged the resurgence of terrorism which poses a national security threat.
Pakistan's military adds that seven surrendered and three were arrested.
The operation marked the latest bout of violence involving the Pakistani Taliban following a fragile peace deal between the group and government that broke down last month, said an official in The New York Times.