Police killed six alleged robbers after a 30-minute car chase that started with a failed highway holdup north of Manila, officials said Wednesday.

The six men, riding in a van, fired on a truck loaded with food products in a robbery attempt late Tuesday in Tarlac province, but the driver sped away and reported the attack to police, Chief Superintendent Ismael Rafanan said.

The robbers were spotted at a police checkpoint but refused to stop, triggering a car chase. Later cornered, the men opened fire on police, setting off a gunbattle that killed all the robbers, Rafanan said.

Police found four pistols and two grenades in the robbers' car, he said.

Among those slain was Darius Zara, who was out on bail for his alleged involvement in a 2003 robbery of a truck loaded with coffee products. During that robbery, Zara allegedly shot two men in the cargo truck, killing one and wounding the other, Rafanan said.

Highway robbery is a perennial problem in many areas of the Philippines.

CountryWatch: Philippines