Gunmen attacked a southern Nigerian oil installation belonging to a subsidiary of Italy's Eni SpA early Thursday, taking three Italians hostage and killing another person, Italian and Nigerian officials said.

Bayelsa state Police Commissioner Hafiz Ringim said "two or three" foreign hostages were taken in the attack on the Agip oil export station.

Click here to go to FOXNews.com's Africa Center.

Italy's foreign ministry said that three Italians were kidnapped.

"The attackers were wearing camouflage and came in about seven boats," Ringim said. "They burnt some vehicles and killed one person."

The identity of the dead man was not immediately clear, although it appeared he was a bystander rather than one of the attackers or an Agip employee, Ringim said.

Such attacks — common in Nigeria's oil-rich southern delta — usually aim to take foreign hostages who can be traded for ransom or political influence.

Since the beginning of 2006, militant groups have attacked pipelines and taken workers hostage in violence that has cut crude output by about 25 percent in Africa's largest oil producer. The West African country would normally expect to produce about 2.5 million barrels daily.

Civilian protesters have also taken over oil facilities to protest a lack of jobs and development. Many of the militants say their attacks and kidnappings are a protest on behalf of a region that has seen little improvement from the oil revenue it produces, but analysts say a recent spate of kidnappings is motivated more by commercial gain. Around 70 foreigners have been abducted so far this year.

Most oil workers kidnapped over the past year have been safely released, but one British hostage was killed last month during a rescue attempt and scores of Nigerians have been killed in militant operations.

Analysts have said that many of the militant groups are linked to local politicians and suggested that recent attacks may be tied to the ruling party's primaries later this month.