A US oil worker has been shot dead in the troubled southern Nigerian city of Port Harcourt.
Rivers State Police Commissioner Samuel Agbetuyi told the BBC attackers on a motorbike shot the man as he was driving his car early on Wednesday.
The BBC's Abdullahi Kaura Abubakar says it is first time a foreigner has been a drive-by shooting victim in the region.
A Nigerian militant group waging a campaign against the oil industry said it had no hand in the killing.
The man's name has been withheld. He worked for oil servicing company Baker Hughes Inc.
In recent months, militants in the southern Niger Delta region have kidnapped foreign oil workers and warned them to leave the Delta. They want more local control of the region's oil wealth.
The upsurge of attacks on foreign oil interests has cut the country's oil production by 20%.
Last month, the Movement for the Emancipation of the Niger Delta (Mend) renewed its threat to continue oil installation attacks.
It said the offer of thousands more jobs and a new motorway from President Olusegun Obasanjo did not address their demands for more local control of oil wealth and demilitarisation.
The shooting follows two car bomb attacks in recent weeks.
The Mend militant group claimed responsibility for them, saying the last one was a warning against Chinese expansion in the region.
Earlier that week, Chinese President Hu Jintao had secured four oil drilling licenses for China in return for $4bn (£2.25bn) of investment in Nigeria.
Most of its previous operations have been in the rivers and creeks of the Delta, rather than urban areas.