Two Chinese nationals were killed in an explosion near the international airport of the southern Pakistani city of Karachi on Sunday night, according to the Chinese embassy in Pakistan, in what it described as a "terrorist attack".

In a statement emailed to journalists, separatist militant group Baloch Liberation Army (BLA) claimed the explosion was an attack carried out by them using a vehicle-borne improvised explosive device targeting Chinese nationals, including engineers.

Pakistan broadcaster Geo News reported at least 10 people were injured in the blast in addition to some fatalities.

The nature of the blast was not immediately clear, Geo News cited a provincial official as saying.

The Chinese embassy said a convoy from the Port Qasim Electric Power Company was attacked near the airport.

"The Chinese Embassy and Consulates General in Pakistan strongly condemn this terrorist attack, express deep condolences to the innocent victims of both countries and sincere sympathies to the injured and (their) families," the statement said, adding the Chinese side was working with Pakistani authorities in the aftermath.

The embassy called for practical and effective measures to ensure the safety of Chinese citizens, institutions, and projects in Pakistan.

"The Chinese embassy and consulates in Pakistan remind Chinese citizens and companies in Pakistan to be vigilant, pay close attention to the local security situation, strengthen security measures, and make every effort to take safety precautions."

The BLA seeks independence for the province of Balochistan, located in Pakistan's southwest and bordering on Afghanistan and Iran.

In August, it launched coordinated attacks in the province, in which more than 70 people were killed.

BLA specifically targets Chinese interests - in particular the strategic port of Gwadar on the Arabian Sea, accusing Beijing of helping Islamabad exploit the province.

It has previously killed Chinese citizens working in the region and attacked China's consulate in Karachi. (Reuters/Xinhua)