Gunmen in Nigeria's oil-rich Niger Delta region have attacked a boat carrying oil industry workers, killing one Nigerian and injuring another person.
The boat's passengers were affiliated with the U.S. energy giant Chevron. Further details of the attack were not immediately available.
Meanwhile, long lines formed at Nigerian gas stations Tuesday ahead of an oil workers' strike scheduled to begin at midnight, local time.
Nigeria's two main oil workers' unions have called a three-day strike to protest violence and kidnappings in the Niger Delta.
The head of one of the unions, Peter Akpatason, described the stoppage as a "comprehensive warning strike" to the government. He said the unions will meet again after the strike to see if their concerns about safety are being taken seriously.
Nigeria's military recently started a campaign against militants who have repeatedly attacked oil facilities in the delta.
The unions called the strike in late August, after a Nigerian employee of Shell oil, Nelson Ujeya, was killed in a shoot-out between militants and government troops.
Nigeria is Africa's largest oil producer, but militant attacks have cut daily production by at least 20 percent this year.
Some information for this report was provided by AP and Reuters.