Armed men on Monday kidnapped four foreign oil workers in Nigeria's southern oil city of Port Harcourt, police said.
"Yes, four oil workers were kidnapped ... And police chiefs are holding a crucial meeting on the issue," said a source in the office of the state police commissioner, on condition of anonymity.
No further detail on the victims was available although unconfirmed reports said they included a Briton and an American.
News of the latest kidnappings followed the release of three Filipino oil industry workers abducted by armed militants 10 days ago.
Cornelio Fallaria, Daniel Monteagudo and Alberto Torres were turned over to embassy officials this morning, Foreign Undersecretary Esteban Conejos told reporters.
The three were abducted on August 4 on Bonny Island, where they were working on a multi-billion-dollar liquefied natural gas project.
Port Harcourt is at the heart of Nigeria's multi-billion-dollar oil and gas industry where many oil firms have their operational base.