"Three Koreans from Daewoo Engineering and Construction, eight Philippine workers and a local driver have been kidnapped by a group of armed insurgents," a foreign ministry spokesman said.

In a separate incident, unidentified assailants kidnapped several employees of Italian energy group ENI who were working on a ship in volatile southern Nigeria, the company said in a statement.

It said there were 85 people on the ship anchored 90 kilometers from Port Harcourt, including 22 foreigners from several countries, when the attack occurred.

The Italian foreign ministry told the Ansa news agency there were no Italians among those held.

Industry sources in Nigeria said five people were taken from the vessel, the Mystras, during the attack, but neither company would confirm this.

The construction site shootout, which happened at the Afam 6 power plant site, lasted for 40 minutes, construction company officials in Seoul said, but refused to confirm a report by Seoul's Yonhap news agency that several people were dead or injured.

"A gunfight erupted between the insurgents and security guards but there have been no reports of injuries involving South Korean workers as yet," the spokesman said.

Local industry sources said the attack happened around 1 am local time. Afam 6 is close to Port Harcourt in the Niger delta.

One source said the attack looked as if it had been carried out with insiude knowledge as the Daewoo managing director among those kidnapped had just arrived in the area.

"Two minibuses of full of armed guys came and shot up the nearest roadblock, then they used dynamite on the Afam 6 gate and perimeter fence," one industry source told AFP.

A total of 1,755 workers including 148 Koreans were at the site, which has been guarded by Nigerian soldiers and security officials, Daewoo spokesman Huh Hyon said.