Islamabad, Feb 11 (DPA) Two back-to-back bombings ripped through a police training centre in Pakistan's restive northwestern region Thursday, killing at least 10 people, officials said.

'There were two blasts with a difference of a few minutes,' said Sardar Mohammad Abbas, the top civil administrator in Bannu district.

Abbas said it was not immediately clear whether they were suicide bombings or remote-controlled explosions. 'For the moment we are carrying out rescue and relief operations.'

An official at Bannu's state-run District Headquarter Hospital said 10 bodies and 25 injured had been moved there. Most of those killed were policemen. 'Seven of the injured are in critical condition,' said health official Waqar Ali Shah.

There were also reports that the district's police chief Iqbal Marwat was injured in the blast, which followed a police operation in the area.

Bannu is 140 km southwest of Peshawar, capital of North West Frontier Province.

No one claimed responsibility for the attack, which took place near the country's militancy-plagued tribal region.

Pakistan is conducting military operations against Taliban and Al Qaeda fighters in the tribal areas near the Afghan border. The militants have retaliated with a suicide campaign that has killed hundreds over the last 12 months.