China said Monday it had lodged a diplomatic protest over the fatal shooting of a Chinese worker in Nigeria and demanded that the African nation take "concrete measures" to better protect its nationals.

Gunmen shot dead the Chinese construction worker in the violence-torn city of Maiduguri on Friday last week, the second killing of a Chinese national in the region this month.

"China's foreign ministry pays high attention to this (incident)," ministry spokesman Hong Lei told reporters.

The Chinese embassy in Nigeria immediately submitted a formal protest and "demanded that Nigeria take concrete measures to ensure the safety of Chinese nationals and institutions in the country," he said.

A Nigerian official confirmed last week that the Chinese worker was shot dead by unidentified gunmen at a construction site in the northeastern Borno state, which has been hit hard by the radical Islamist group Boko Haram.

On October 7, gunmen killed a Chinese national who was working for a construction company in the town of Gubio, near Maiduguri.