KARACHI, Pakistan

At least nine army personnel were killed in an ambush in southwest Pakistan on Tuesday, government sources said.

The incident, the latest in a string of attacks on security forces, occurred in the Washuk district of southwestern Balochistan province.

There has been no official confirmation of the incident from the Pakistan army so far.

No group has claimed responsibility for the attack till the publishing of this report.

The incident comes a day after the US declared two key militant groups operating in the region - Balochistan Liberation Army and the Majeed Brigade - "terrorist" organizations.

The mineral-rich Balochistan province has long been a hotbed for militancy, where the army has been facing a low-intensity rebellion.