"Around 40 to 50 armed terrorists attacked a border post manned by the Frontier Corps Balochistan in Kalat district, killing seven soldiers and wounding 15 others," a local official told AFP on condition of anonymity.

"The exchange of fire lasted several hours," he added.

A local civilian administrative officer confirmed the number of casualties, adding that the wounded were "airlifted from this remote area to (provincial capital) Quetta for medical treatment".

Jeeyand Baloch, a spokesman for the Balochistan Liberation Army (BLA) separatist group, claimed responsibility for the attack without giving further details.

The BLA frequently claims deadly attacks against security forces or Pakistanis from other provinces, notably Punjabis.

Militants have targeted energy projects with foreign financing -- most notably from China -- accusing outsiders of exploiting the resource-rich region while excluding residents in the poorest part of the country.

Prime Minister Shehbaz Sharif condemned the "terrorist attack" in a post on X on Saturday, promising that "immediate action will be taken against the perpetrators".

The latest attack comes a week after the BLA killed 26 people, including 14 soldiers, at a railway station in Balochistan, which borders Afghanistan and Iran.

The BLA said the earlier attack "was carried out on a Pakistani army unit at Quetta railway station... after completing a course at the Infantry School."

In August, the BLA claimed responsibility for coordinated attacks by dozens of assailants who killed at least 39 people, one of the highest tolls to hit the region.