The rebels have attacked a number of power installations

Three soldiers were killed and seven wounded while three of the rebels also died and blood trails indicated a number of wounded too, the army said.

The New People's Army has been waging a campaign to install a Maoist state in the Philippines, a strong US ally.

President Gloria Arroyo faces elections in May and the Communist Party has warned of increased insurgency.

Communist Party spokesman Gregorio Rosal said that the attack was "in response to the directive of the party to intensify tactical offensives".

He said it was intended to punish soldiers in the area for what he called human rights abuses, rather than to damage the power station.

"The attack was directed at the detachment. In truth they did not do anything to [the facility]," he told a local radio station.

'Secured'

Saturday's fire-fight at the coal-fired plant in Calaca, about 80 km (50 miles) from Manila, raged for some 15 minutes.

About 50 guerrillas took part in the attack on the 600-MW station, which serves the main Philippine island of Luzon, and was guarded by about 10 soldiers and 30 militiamen.

A military spokesman said the rebels drove up to the power station in a lorry and fired at least two light anti-tank rockets.

Reinforcements were called and the guerrillas were pursued as they fled.

"The power plant is secured and operational," said Dennis Gana, a spokesman for the National Power Corporation.