Gunmen in military camouflage have killed four guards at a facility operated by the Nigerian subsidiary of Italian group Eni. Four members of the Nigeria Security and Civil Defence Corps (NSCDC), a paramilitary agency of the government, were killed on Monday at the installation at Omoku near Port Harcourt, they said.
"The security operatives had engaged the gunmen in a fierce gun battle on realising that the intruders were not military men," state NSCDC spokesman Michael Oguntuase told AFP.
A community leader in Omoku who did not want to be named confirmed the incident.
"Dressed in camouflage, they came in a speed boat at about 18:40 on Monday, exchanged gunfire with the operatives, leading to the death of four," he said.
An unspecified number of NSCDC personnel were wounded, he said.
Officials at Agip, the local subsidiary of Eni, were not immediately available for comment.
There has been no claim of responsibility for the attack.
Since the start of the year several militant groups, Including the Niger Delta Avengers (NDA), have bombed pipelines and facilities operated by oil companies.
The attacks have slashed Nigeria's oil output, hammering government revenue at a time of global low prices.