Beijing is pushing Pakistan to allow its own security staff to provide protection to thousands of Chinese citizens working in the South Asian nation, during talks after a car bombing in Karachi that was seen as a major security breach, sources said.

Last month's airport bombing in the southern port city that killed two Chinese engineers returning to work on a project after a holiday in Thailand was the latest in a string of attacks on Beijing's interests in Pakistan.

The attacks, and Islamabad's failure to deter them, have angered China, which has pushed Pakistan to begin formal negotiations for a joint security management system.