Unknown gunmen have killed a Lebanese construction worker on his way to work in Nigeria's oil-rich city of Port Harcourt, say security sources.
Delta militants have carried out a series of attacks and abductions
They opened fire on two Lebanese workers, although other details of the attack remain sketchy.
Industry sources describe the attack as "unusual" as it seemed deliberate.
The shooting is the latest in a growing number of incidents targeting foreign workers in the Niger Delta region which has seen oil exports cut by a fifth.
"Normally, the militants just kidnap the foreigners, but this one is different as we are being told that the attackers deliberately opened fire on them as if it was planned," a senior security official with a major western oil company told the BBC News website on the phone from Port Harcourt.
Senior police officers in Port Harcourt are meeting about the shooting.
Meanwhile, the Italian foreign ministry has confirmed that two Italian construction company employees have been kidnapped near Port Harcourt.
A militant group in the Niger Delta is already holding two Italian citizens.
On Thursday, it issued a warning after it said a Lebanese hostage had escaped captivity and had not been freed, as his company earlier claimed.
It is the first time a hostage has escaped during a year-long wave of kidnappings in the Delta, which has seen more than 100 hostages taken.
The group says the man escaped with the help of the local state government and his employer, Italian oil company Agip, and warned they would seek vengeance.
They also said they would halt negotiations on the release of Italians being held hostage.
The group's leaders say they want the release of two prominent local leaders and compensation from oil companies for pollution in the Delta.
Most kidnapping cases in the Delta are resolved after a ransom has been paid.