At least 20 people were feared killed and 30 others wounded when suspected militants hurled hand-grenades and fired on people offering prayers in a mosque in northwestern Pakistan late on Wednesday night. 

''Militants surrounded the mosque, threw grenades and then started indiscriminate firing, killing 20 people and wounding 30 others,'' Dawn newspaper reported.  Local media reports, meanwhile, quoted officials as saying that the death toll could rise.

The village in Miskene area, where the carnage took place, is near the Afghan border in lower Dir town and has recorded the presence of militants. 

''There was a possibility of the presence of militants in the area, being close to the border, but nothing could be said with certainty about the elements involved in the attack,'' an official said. 

The station head officer of nearby Samarbagh police station said he had heard from local people that 15 people had been killed and 20 others were wounded. He claimed that the miscreants first tossed hand-grenades and then started firing indiscriminately.

 ''We were offering prayers when these people lobbed explosives into the mosque, causing a series of explosions,'' said a local man, adding that the mosque was crowded and there were children as well. 

The area is close to Bajaur tribal region where security forces have been engaged in a massive operation to flush out terrorists.  More than 500 people have been killed and more than 260,000 displaced in Bajaur since the launch of the operation in early August.