Six people were wounded after leftist rebels detonated bombs along a national highway in southern Philippines on Tuesday, the military said.

The incident along the Pan-Philippine highway in Magdum village, Tagum City, Davao del Norte province, at around 6 a.m. local time injured five soldiers and a civilian woman, according to Lt. Vilma Mojado, spokesperson for the 10th civil military operations battalion.

The victims were on board a KM-450 military truck of the army's 66th Infantry Battalion when an improvised explosive device believed planted by the leftist New People's Army went off by the roadside.

Mojado said another landmine also exploded in nearby Mawab town, along the same stretch of road, an hour later, but did not cause casualties.

She said the victims are now undergoing treatment at a local hospital as pursuit operations against the rebels has been launched.

The 4,000-strong NPA, armed wing of the Communist Party of the Philippines, is fighting a leftist insurgency in 60 Philippine provinces since 1969.