(Adds details on captive's employer, paragraph 2)

ABUJA, April 7 (Reuters) - Gunmen kidnapped two Turkish engineers from their car in Port Harcourt in Nigeria's oil-producing Niger Delta, police said on Saturday.

One of the men works for Merpa, a Turkish firm that maintains telecoms equipment on one of the oil platforms of Italian firm Agip in the delta, said Agip's parent company Eni. The employer of the second captive was not known.

"They were intercepted by militants when they were driving late yesterday evening," said Felix Ogbaudu, police commissioner of Rivers State, where Port Harcourt is located.

Kidnappings for ransom or to press for benefits from oil firms are common in the Niger Delta, a vast wetlands in southern Nigeria that accounts for all oil production from the world's eighth-biggest exporter.

Most kidnap victims are released unharmed after a few days, though some have been kept in captivity for months and two have been killed in botched attempts by troops to free them.

Thousands of expatriate workers and their relatives have left the Niger Delta since the start of a wave of attacks on oil facilities and kidnappings of foreigners in late 2005.

Oil production has been reduced by 500,000 barrels per day, one fifth of Nigeria's production capacity, since a series of raids on Royal Dutch Shell oilfields in February last year forced their closure.

Violence in the delta is rooted in poverty and frustration at the lack of benefits for local people from an industry that has polluted their land, air and water for five decades.

Nigeria made $40 billion from oil exports last year, but most people in the delta have no access to clean water, electricity, roads or doctors because widespread corruption in government has led to a collapse in basic public services.

As a result, many local communities expect oil firms to step in where government has failed to and provide jobs, infrastructure and development projects.

But the lines between militancy and crime are blurred in the delta. Some armed groups have taken hostages to press political demands but many "freelance" kidnappers have seized foreigners to extract cash from their companies or from government. (Additional reporting by Phil Stewart in Rome)

AlertNet news is provided by