MANILA, May 16 (Reuters) - Communist rebels killed seven Philippine soldiers on Wednesday in a dawn ambush in a northern province already wracked by election-related violence.

Over 120 people have been killed during campaigning for congressional and local elections on May 14 and the military had warned the communist New People's Army would step up its insurgency while votes are still being counted.

Senior police inspector Dennis Agno said 100 NPA guerrillas attacked a team of troops at around 6:30 a.m. (2230 GMT Tuesday) in a remote town in Abra, where at least six people have already been killed in a feud between rival political clans.

The military had already blamed the NPA, which has been waging a communist insurgency since 1969, for an arson attack that killed two teachers on Tuesday.

Violence is a feature of Philippine elections due to rivalry for lucrative public seats, a gun culture and communist and Muslim insurgencies. In the presidential vote in 2004, at least 189 people were murdered.

Final election results will take up to one month but supporters of President Gloria Macapagal Arroyo are expected to sweep the race for the 275-member House of Representatives and a majority of 18,000 local government posts.

Arroyo's opponents, however, are expected to regain their majority in the Senate.

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