Pakistan military bases attacked, 20 dead

Insurgents in the Pakistani province of Balochistan have attacked two military bases, killing seven soldiers while losing 13 of their own men, the army says.

The attacks came hours before Pakistani Prime Minister Imran Khan set off for the opening of the Winter Olympic Games in Beijing, where he will have meetings with Chinese President Xi Jinping and other leaders.

"Our armed forces repulsed the big attacks," Minister of Interior Sheikh Rasheed Ahmad said in a video statement on Thursday.

He had previously put the toll at four soldiers and 15 attackers, but a Pakistani army statement later said a total of seven soldiers and 13 insurgents were killed.

Some of the attackers were still encircled by the military, it said.

The Baloch Liberation Army (BLA) group claimed responsibility in a statement, saying its suicide bombers had detonated explosive-laden vehicles at the entrance of the bases killing more than 50 soldiers.

Last week, the insurgents killed 10 soldiers in an attack on a post near the port of Gwadar on the Arabian Sea, the heaviest casualty toll for the army in the Balochistan insurgency in years.

Ethnic Baloch guerrillas have been fighting the government for decades for a separate state, saying the central government unfairly exploits Balochistan's rich gas and mineral resources.

They usually attack gas projects, infrastructure and the security forces. They also attack Chinese projects, and occasionally kill Chinese workers despite Pakistani assurances that it is doing everything it can to protect the projects.

China is involved in the development of the Gwadar port and other projects in the province as part of a $US60 billion ($A84 billion) China-Pakistan Economic Corridor, which is part of Beijing's Belt and Road initiative.