Militants killed at least three Pakistani soldiers in an attack early Saturday on a border post in the restive northwestern tribal belt, officials said.

Around two dozen militants armed with sophisticated weapons crossed from the Afghan province of Kunar to launch the pre-dawn ambush in Bajaur district, Pakistani officials said.

"Militants from across the border ambushed a check post. Two security personnel and an officer embraced martyrdom in the attack," a security official in Bajaur told AFP by telephone.