An ambush on a security detail accompanying a convoy of Pakistan’s state-owned Oil & Gas Development Company (OGDC) in Balochistan has left at least 14 dead.

The security contingent has accompanying OGDC personnel on a coastal highway between the port town of Gwadar to the nation’s commercial capital Karachi.

OGDC workers and paramilitary troops were among those killed in the attack on a highway in Gwadar, according to news wire AFP, but this could not be independently confirmed.

Seven soldiers and seven private security guards were killed in the attack, which was carried out by "a large number of terrorists," local media quoted the military said in a conflicting statement.

An umbrella organisation of Baloch militant groups, Baloch Raaji Aajoi Sangar (BRAS), has claimed responsibility for the attack.

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In a statement obtained by CNN, the alliance said that "companies like the OGDC are exploiting Baloch resources in their strategy of extending the occupation of Balochistan”.

Balochistan has seen a decades-long insurgency by separatists who demand independence from Pakistan, protesting against the state's control and exploitation of the province's hydrocarbon and mineral resources.

Last Thursday’s attack is the deadliest this year on Pakistani military. The Baloch Liberation Army in June attacked the Karachi Stock Exchange, killing five people.

Balochistan, which borders Iran and Afghanistan is the poorest in Pakistan despite its oil and gas resources.