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 neighbor as part of a plan unveiled in 2015 to link its far-western Xinjiang region to Gwadar port in Baluchistan 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 Baluchistan province, which is at the heart of the China Pakistan Economic Corridor (CPEC) project but racked by insurgencies.

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

China has stated it will cooperate with Pakistani authorities to investigate whether the two Chinese citizens -- who were allegedly killed by the Daesh group in the country -- had been illegally preaching.

So far there has been no official confirmation of the Chinese pair's fate.

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

The Daesh group has been making inroads in the country through alliances with local militant outfits, although its presence is generally downplayed by the government.