MANILA, Philippines – A bomb exploded outside the House of Representatives late Tuesday, killing a Muslim rebel-turned-congressman who had backed a U.S.-Philippine offensive against Islamic militants. A lawmaker’s driver and a legislative staffer also died.

The remotely detonated bomb collapsed the ceiling at the building’s entrance, damaged cars and injured seven people, including two congresswomen. Their injuries were not life threatening.

“I felt the blast although I was on the other side of the building,” Rep. Teodoro Casino said.

Interior Secretary Ronaldo Puno said the target appeared to be Rep. Wahab Akbar, a former rebel who as governor of southern Basilan province gave his support to military operations against al-Qaida-linked Abu Sayyaf guerrillas. Akbar died of wounds in a hospital, police said.

Puno sought to play down the possible involvement of Muslim extremists, however, saying the investigation was “pointing away from terrorist attack and more of a directed assault on a certain individual.”

While he turned on the Muslim rebels, Akbar also had many political foes, including those who ran against one of his wives who succeeded him as Basilan governor. Political rivalries in the southern Philippines are often accompanied by bloodshed, and assassinations of politicians are common.

At the bombing scene, national police chief Avelino Razon said a destroyed motorcycle was found and experts were conducting chemical tests to determine if it was used to carry the bomb.