Kabul: At least 30 Taliban militants were killed in an accidental blast in Afghanistan's Farah province, an official said on Friday.

The explosion took place in Pewa Pasaw area of Bala Buluk district on Thursday before the militants tried to attack government security forces' positions, Xinhua news agency quoted the official as saying.

"As soon as the militants were getting ready for the assault, the jacket of a would be suicide bomber detonated prematurely, setting off a handful of explosive," he said.

Many militants were injured in the blast, the official said.

Taliban militants have been on the rampage since April when they launched an annual rebel offensive in Afghanistan, killing and injuring hundreds.

The province bordering Iran has been the scene of clashes between security forces and Taliban militants over the past years.

The Taliban militant group is yet to make comment.