Government spokesman Issa Tchiroma Bakary said late Wednesday that two more people were kidnapped than previously thought. Officials believe the hostages are being held in neighboring Nigeria.
Pirates kidnapped the officials on Sunday, and killed two paramilitary policemen Monday.
No one has claimed responsibility but officials believe it was the work of the Bakassi Freedom Fighters, a militant faction disputing Cameroon's ownership of the oil-rich tongue of land.
Bakassi was officially handed over to Cameroon in August 2008 following a verdict two years earlier by the International Court of Justice.