Heavily-armed communist guerrillas burned heavy equipment and robbed mobile phones and radio communications equipment during raids at two coal mines in the central Philippines, police said on Friday.

Active in 69 of 81 provinces across the country, the New People's Army is viewed by the government as its most serious security threat, scaring away potential foreign and domestic investors and slowing economic growth.

The 5,000-member rebel group has vowed to step up attacks on private businesses and particularly targets mining companies.

We believe the rebels were trying to send a message to the owners of the coal mines after they refused to give in to demands for protection money, said Isagani Cuevas, regional police chief on the central Panay and Negros islands.

He provided no details on the mines' owners.

Cuevas said no one was hurt in the raid in Calatrava town on Wednesday night.

The attack came 30 minutes after another group of NPA rebels raided a port in Escalante town, also on Negros island, and burned trucks and robbed workers of money and jewellery.

In both attacks, the rebels cut off power and telephone lines to prevent workers at the mines and port from calling for help. (Reporting by Manny Mogato; editing by Carmel Crimmins)

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