Chinese workers at Gwadar port. -AFP

ISLAMABAD: Pakistan has deployed a 15,000-strong military force to protect Chinese nationals working on energy and infrastructure projects in the country, the president said Sunday, after the abduction of a Chinese couple raised safety concerns.

President Mamnoon Hussain told visiting Chinese Foreign Minister Wang Yi in Islamabad that the protection of Chinese citizens working in Pakistan was the "top priority" of the government, according to a statement issued by the presidency.

Beijing is investing around $50 billion in its South Asian neighbour as part of a plan unveiled in 2015 to link its far-western Xinjiang region to Gwadar port in Balochistan with a series of infrastructure, power and transport upgrades.

But fears over safety arose last month when two Chinese workers were abducted in Quetta, the capital of the southwestern Balochistan province, which is at the heart of the China-Pakistan Economic Corridor (CPEC) project but racked by separatist and militancy.

Authorities were going to all possible efforts to arrest those responsible for kidnapping, Hussain said.

Pakistan has been battling militancy and insurgencies in Balochistan since 2004, with hundreds of soldiers martyred and militants killed in the fighting.