Nine Chinese oil workers are missing after being attacked by an armed group in Nigeria on Thursday, Chinese Foreign Ministry spokeswoman Jiang Yu confirmed here yesterday.

A Chinese oil company compound was attacked by an unidentified group in southern Nigeria. Nine workers were missing and the others had been removed to a safe place, according to a statement from China's Foreign Ministry.

Officials were still verifying the identities of the missing workers, it said.

China was working closely with other parties to ensure their safe return, according to the statement.

A spate of attacks and kidnappings on foreign companies and workers have occurred in Nigeria, the largest oil producer in Africa and the sixth largest oil exporter in the world with a daily output of 2.5 million barrels.

The attack came four days after five Chinese telecom workers returned home after being held hostage in Nigeria. They were captured by unidentified armed men on Jan. 5 in the southern Nigerian state of Rivers and released 13 days later on Jan. 17.

China's Foreign Ministry warned on Wednesday of the serious security situation in Nigeria.

In a travel advisory on its website, the Foreign Ministry said attacks and kidnappings on foreigners were frequent in southern Nigeria, and warned Chinese companies and workers there to enhance awareness of security, and stay out of dangerous regions.

Nigerian group of the Movement for the Emancipation of the Niger Delta has kidnapped 24 Filipino seamen from a cargo ship in Nigeria's southern state of Delta, local newspaper reported last Sunday.

The Philippine government said Friday that there had been no breakthrough in talks with the kidnappers so far.

On Tuesday, Nigerian police confirmed that two Americans were kidnapped on Tuesday in Nigeria's southern state of Rivers.