Kidnappings are common in the West African nation's oil-rich region. Hostages are usually returned unharmed after a ransom is paid although injuries and fatalities have occurred.
Musa said earlier that two oil workers -- one Nigerian and one Filipino -- were kidnapped Friday in a similar incident. Late Thursday, five eastern European oil workers were abducted from a Swedish boat in the delta, security sources said on condition of anonymity because they were not authorized to speak to the media.
Despite being the home of vast petroleum reserves, Nigeria's south is as desperately poor as the rest of the country. Attacks on oil infrastructure have trimmed about a quarter of the country's total oil production, helping push world crude prices to historic highs.