The six, and a French colleague freed earlier this week, were part of an oil exploration team working in the Congo near the Angolan enclave of Cabinda.
To add to these headaches, there are disquieting developments in Cabinda.
Cabgoc's Cabinda offshore concession contributed about 45-50 per cent of national production in 1990.
He said the commandos were sent to blow up the depot belonging to Cabinda Gulf Oil, a subsidiary of the U.S. oil company Chevron.