Gunmen have kidnapped two Chinese men and a Nigerian man working for a local company in the southeastern state of Anambra, police said on Monday.

This report was also confirmed by the Chinese Foreign Ministry on March 20, saying the Chinese side is trying to verify the matter and negotiate with the Nigerian side.

The ministry urges the Nigerian side to do its utmost to rescue the workers.

The Chinese were the first foreigners kidnapped outside of Nigeria's oil heartland in the southern Niger Delta.

The men were abducted from their workplace in the industrial town of Nnewi on Saturday, March 17 raising concerns a spate of hostage-taking in the Niger Delta may be spreading to other parts of Nigeria.

Police said they were yet to establish who the kidnappers were and what their demands might be.

"The two Chinese nationals and one Nigerian were kidnapped at the place where they were working. We are investigating the matter," a police spokesman said by telephone from the state capital Awka.

He said the police suspect a separatist group operating in the southeastern region may be behind kidnappings the men from the premises of the Innoson Group of Companies Ltd.