Manila, Sep 1 : Five Philippine government militiamen were killed and three others wounded in an ambush on Friday by suspected New People's Army (NPA) rebels in Quezon province, southeast of Manila, a military spokesperson said. Dennis Cana, spokesperson of the military's Southern Luzon Command said the attack occurred around 7:00 a.m. local time while the government forces were on patrol in Tagkawayan town to investigate the presence of an undetermined number of NPA fighters, Xinhua news agency reported. The militiamen were members of the Civilian Armed Force Geographical Unit, a paramilitary force helping the military in a counter-insurgency campaign against the NPA rebels. Additional troops were also sent to the clash site to pursue the fleeing rebels, Cana added. NPA rebels have been fighting the government troops since 1969. They concentrate their attacks on rural areas and have skirmishes with the military. Military data showed that the NPA is estimated to have 2,000 members, significantly lower than its peak strength in the 1980s. /IANS