Seven police commandoes have been killed in a bomb and gun attack by communist rebels in the northern Philippines, officials say.

Rebels from the New People's Army (NPA) ambushed the group as they made their way to a medical exam.

Their truck was hit by an explosion, after which the militants opened fire, police said. Seven other commandoes were also injured in the attack.

The incident took place near Allacapan, 400km (250 miles) north of Manila.

Those who died were members of an elite counter-insurgency police unit, reports said.

The NPA has been fighting for a communist state for more than four decades.

One of Asia's longest-running insurgencies, the group concentrates its campaign in rural areas and in small-scale skirmishes with the military.

A recent push for peace talks collapsed earlier this year.

The group is listed on the Foreign Terrorist Organisation list of the US State Department.