Two sailors, one Russian and the other Nigerian, have been kidnapped from a ship belonging to French oil-industry-services company Bourbon off Nigeria's coast, the company says.
The ship was hijacked by pirates in the Gulf of Guinea, but the crew managed to send a distress call.
Nigeria's navy assaulted the ship and rescued most of the crew. However, the hijackers got away with two hostages, authorities said.
Bourbon saidon February 24 that 10 crew members were "back on board the vessel in Onne port, safe and sound."
In April 2015, another of the company's boats was attacked off Nigeria and three crew members were taken hostage. They were freed unharmed one month later.
In recent years oil company employees have become a target for armed groups, which also regularly sabotage the oil infrastructure in Nigeria, Africa's top crude producer.
Oil accounts for some 90 percent of OPEC-member Nigeria's foreign-exchange earnings.