Authorities say a Pakistani guard shot and wounded two Chinese nationals working in a textile mill in the southern port city of Karachi, but the attack was not related to militant violence.

Two Chinese nationals were shot at and injured on Tuesday in Pakistan's commercial hub of Karachi, police and hospital officials said, after a string of attacks that spurred Beijing to demand tougher security for its citizens.

Authorities in Pakistan said Tuesday that a local security guard at a factory in the southern port city of Karachi shot and injured two Chinese nationals, the third attack this year in the country targeting workers from China.