Manila  - A soldier and a civilian woman were killed Wednesday in a bomb attack by suspected Muslim separatist rebels in the southern Philippines, an army spokesman said.

Four soldiers were also injured in the blast in Datu Unsay town in Maguindanao province, 930 kilometres south of Manila, according to Lieutenant Colonel Jonathan Ponce.

The soldiers were washing their clothes in a creek about 100 metres away from their outpost, Ponce said.

"The soldiers were unarmed," he said. "There were also other civilians washing clothes in the creek."

Ponce blamed the Moro Islamic Liberation Front (MILF) for the attack.

"It was the special operations group of the MILF that planted the bomb," he said. "This attack is a gross violation of the law of war. They should not attack civilians and unarmed soldiers."

The MILF is the largest Muslim rebel group fighting for a separate Islamic state in the southern region of Mindanao. It has been waging the secessionist struggle since 1978.

Peace talks between the MILF and the Philippine government have been suspended since August 2008 when the rebels launched a series of deadly attacks in Mindanao.

Nearly 300 people were killed and more than 500,000 were displaced due to the rebel attacks and subsequent fighting between the MILF and the military. (dpa)