Police: 4 South Koreans, 1 Nigerian kidnapped in Nigeria's southern delta

Police say kidnappers are holding hostage four South Koreans and a Nigerian working for a Korean company in Nigeria's oil-rich southern delta.

Bayelsa State police spokesman Fidelis Odunna said Tuesday that gunmen attacked the company's offices Monday in the area of Brass.

Odunna said a Nigerian was freed soon after the attack, leaving five colleagues in captivity. Police suspect he was set free because he is from the area where the kidnapping occurred.

Odunna said there had not been any ransom request and police are investigating.

The kidnapping comes a week after Nigeria's finance minister's mother was abducted in nearby Delta State. She was freed five days later. Authorities have declined to say if a ransom was paid.

Nigeria's oil-rich delta is a kidnapping hotspot, but many cases go unreported.