Islamabad: About 100 Taliban fighters attacked a security check post in Pakistan's restive tribal belt, triggering a clash that left 14 militants and three security personnel dead, officials said on Monday.

The officials told the media that around 100 militants armed with sophisticated weapons attacked Ulay check post in Baizai area of Mohmand tribal region overnight.

The militants killed three security personnel.

The security forces returned fire, killing 14 militants early this morning, the officials said.

State-run Radio Pakistan reported that seven security personnel were missing after the attack by the militants.

Security forces have launched a "full-scale operation" to clear the area of militants, the officials said.

The check post that was attacked is located in an area that borders Kunar province of Afghanistan.

The clash occurred near Salala area, where 24 Pakistani soldiers were killed in a cross-border NATO air strike in November last year.

The check post at Ulay was set up after the check post at Salala was destroyed in the air strike.