Two other lawmakers and five more persons were also wounded in the explosion, just minutes after the House adjourned its plenary session a little past 8 p.m.

Aside from Akbar, the explosion also killed Marcial Tando, driver of Gabriela party-list Representative Luzviminda Ilagan, and 30-year-old Maan Gale Bustalino (not Bustanillo as earlier reported), a member of the staff of Negros Oriental Representative Pryde Henry Teves.

Both Ilagan and Teves were also wounded in the explosion.

House Speaker Jose de Venecia said a bomb caused the explosion, which came on the eve of the resumption of a congressional hearing that is likely to result in the squelching of an impeachment complaint against President Gloria Macapagal-Arroyo.

"I mention the possibility of a terrorist, an anarchist or an extremist who wants to destabilize ... the national government," De Venecia said.

In a televised statement at midnight, Ms Arroyo said she would like to assure Filipinos and foreign countries that her government would hunt down those responsible.

"We call on the people to avoid speculation, allegations and rumors that might create confusion, fear and divisions," she said.

Philippine National Police Director General Avelino Razon Jr. said Doctor Arnold Corpus declared the congressman dead at the Far Eastern University Hospital at around 10:25 p.m.

Ms Arroyo went to the hospital a little past 1 a.m. to condole with Akbar's family. From there she proceeded to St. Luke's Medical Center at around 2 a.m. where Representatives Ilagan and Teves and three other victims were being treated.

She went straight to the rooms of the lawmakers, who have been both declared in stable condition after sustaining injuries from the blast.

Ilagan said she was walking to her car when "there was a sudden explosion."

"I was heading to my car because the session had already adjourned. When we were going down the south wing, there was a sudden explosion," Ilagan said from a hospital. "I managed to walk but after a while I stumbled and realized my feet were bloodied and I couldn't stand up anymore," she told Agence France-Presse.

"My driver did not make it," she added.

Mayor Talib Pawaki of Hadji Muhamad Ajul town in Basilan province said Akbar sustained "massive head injuries," including a fracture, but was still alive when brought to the hospital.

Akbar's body will be flown home to Basilan at 3 a.m. Wednesday on a C130 plane in keeping with Muslim tradition to bury the dead within 24 hours.

National Capital Region Police Director Geary Barias said Akbar was the likely target of the bombing but added that they still had to confirm this.

He said Tando, who was identified through his identification card, died on the spot and suffered "a very big wound" in his nape. His body will be brought either to the police crime laboratory or the National Bureau of Investigation for autopsy.

Iloilo Representative Janet Garin, a medical doctor who helped evacuate the wounded, told news television that Bustalino died at the Capitol Medical Center where she was rushed when her vital signs deteriorated as she was being transferred to the St. Luke's Medical Center from the General Miguel Malvar hospital on Commonwealth Avenue.

Barias said they suspect an improvised explosive device was apparently left on a motorcycle parked near Ilagan's vehicle and was remotely detonated because "the explosion occurred immediately after the suspension of the session at 8:05 p.m."

He could not immediately describe the type of explosive. He said no bomb parts so far had been retrieved.

He added that they were looking at one of two motorcycles parked a few meters from the south wing lobby of the Batasan as the carrier of the bomb. The explosion left a three-foot crater.

He said they are questioning a cameraman of the House of Representatives who owned one of two motorcycles but were not taking him into custody.

Gabriela party-list Representative Liza Maza, also identified another of the wounded as her driver Mike Lim. She said Ilagan, Lim and Tando were rushed to the nearby Miguel Malvar Hospital.

Although he suffered blast injuries, including second and third degree burns and shrapnel wounds to the face and body, Teves was no longer in serious condition, his grandfather and predecessor, Herminio Teves, told INQUIRER.net .

Earlier, Dr. Ven Malabanan of the New Era General Hospital, where Teves was first rushed, said the solon was in "very critical condition" and had to be transferred to St. Luke's. "He had to be transferred because he needs to be [admitted to] the Intensive Care Unit," Malabanan said.

Two other victims, Nulasiri Hayugini (not Julasiri 'Niki' Hayudin as earlier reported) and Denis Manila remain at New Era. Dr. Mike Brillantes described Hayudini as also in critical condition, with shrapnel wounds and burns all over her body and a left leg that might have to be amputated.

Malabanan also said Hayugini is intubated and unstable while Manila might need to undergo surgery for deep shrapnel wounds.

Maza said she had looked out her office window on hearing the explosion and saw Ilagan's car on the driveway of the south wing of the Batasang Pambansa in Quezon City and next to Akbar's Fortuner sports utility vehicle, which was on fire.

Representatives who were still inside the Batasan when the explosion occurred were initially prevented from leaving to allow police to clear the building.

The Gabriela solon said she and Ilagan had left the session hall together but her colleague went straight to the south wing to leave while she passed by her office.

"I heard a loud explosion and thought at first it was thunder but realized it was too loud to be thunder," Maza said. "When I looked out my window, I saw a vehicle on fire and near that vehicle was the car of Congresswoman Ilagan."

She said she immediately sent a member of her staff down to check the situation and was told "there were bodies sprawled throughout the lobby."

Reacting to Akbar's death, Secretary Jesus Dureza, presidential adviser on the peace process, said: "I am saddened to know that a good friend and a leader in Basilan is among the casualties. Whatever the reasons and motives are, whether he is the target or the intended victim, we would have to leave that to the authorities to investigate."

"We grieve for him," he told Agence France-Presse.

He said Akbar had helped the government in its anti-terrorism campaign against the Abu Sayyaf group on Basilan island, where the militants are on the run from a massive military manhunt.

Akbar, 47, had twice served as governor of Basilan, a known stronghold of the extremist Abu Sayyaf.

He had spoken in the past of links to Abubakar Abdurajak Janjalani, an Afghan-trained Islamic firebrand who founded the Abu Sayyaf.

Janjalani was killed in a gunbattle with police in 1998, and Akbar severed ties with the group, later joining the mainstream and seeking an elective post.

Akbar also had known political enemies in Basilan, where politicians maintain private armies and often engage authorities in attacks.

De Venecia said he had ordered a "clean sweep" of the sprawling Batasan complex to ensure "there are no other bombs that are left behind."

Congressman Joel Villanueva said less than 50 of the House's 275 members were left inside when the bomb exploded.

"It was a very huge explosion," Villanueva said. "We are stunned."

"I heard it and I felt the blast although I was on the other side of the building. The ceiling of the canopy near the south wing entrance came down," Bayan Muna (People First) party-list Representative Teodoro Casiño told The Associated Press.

Philippine National Police Director General Avelino Razon, who has arrived at the Batasan, is under orders from Ms Arroyo to personally supervise the investigation of the explosion, Press Secretary Ignacio Bunye said.

Bunye said Razon is under instructions to determine the cause of the explosion and make periodic reports to Arroyo.

De Venecia said the usual House session would resume Wednesday after an overnight security sweep of the Batasan compound. "We have to show that we are not afraid of terrorists," he said.

He condemned "in the strongest terms this cowardly and dastardly attack against the House of Representatives."

"I was lucky. I had left a few minutes before the explosion," De Venecia said. "There are many threats against us personally, against some members of the House."

He said he had spoken with the Ms Arroyo. "The President is very concerned about what took place here because it was only a few weeks ago that the Glorietta incident took place.

Rep. Prospero Nograles said that the bomb attack at the Batasan was a first. He said security measures were being reviewed there. He said security was lax Tuesday night, pointing out that a pre-Christmas flea market had been set up on the Batasan grounds by the employees' cooperative.

Troops went on heightened alert in Metro Manila and checkpoints were set up in strategic streets.

The House explosion occurred amid heightened political tensions in the country, with Arroyo facing a third impeachment complaint in as many years amid a barrage of political storms, corruption scandals and a feisty opposition.

Metro Manila has been jittery since last month, when an explosion ripped through the Glorietta 2 mall in Makati City, killing 11 people and injuring more than 100. Police say the mall explosion was an accident.