Philippine police suspect a bomb at the House of Representatives that killed a congressman and two other people Tuesday night may have been triggered by a cell phone. In the aftermath of the explosion, the entire security force at the Philippine Congress has been changed. Douglas Bakshian reports.

Police say initial indications are that the bomb was in a motorcycle at an entrance to the House of Representatives, and investigators have found parts of a cell phone that may have been used to trigger the device. Metro Manila Police Chief Geary Barias told ABS-CBN television that a person at the scene may have detonated the bomb.

"On site. In other words the device was under the control of the suspect. He would say when the bomb gets off," said Barias.

There was no immediate explanation of how a bomber was able to penetrate security in the building. Avelino Razon is director-general of the Philippine National Police, or PNP. He says security in the House and Senate has been changed, from one police unit to another, until the authorities have a better idea of what happened.

"We have relieved the entire PSOP security force and changed them with a company of PNP-SAF effective this morning," Razon said. "And that also goes with the contingency force in the Senate."

Congressman Wahab Akbar of the southern island of Basilan was killed in the blast. He is a former Muslim rebel who supported a military campaign against Islamic militants of the Abu Sayyaf terrorist group on Basilan.

The region is known for violent political disputes, and authorities say Akbar had many political foes and had received death threats. However, no one has claimed responsibility for the blast, and no suspects have yet been arrested or identified.

Members of Congress went back to work Wednesday in a sign that they will not be intimidated by the violence. President Gloria Macapagal Arroyo has put Manila and the region around the capital on a state of alert.