ALGIERS, Algeria - Two convicted terrorists who had been freed in an amnesty carried out Tuesday's suicide bombings at U.N. and government buildings, an Algerian security official said yesterday.

One of the bombers was a 64-year-old man in the advanced stages of cancer, and the other was a 32-year-old from a poor suburb that has produced many Islamic extremists, the official said on condition of anonymity because he was not authorized to speak to the media.

The government has offered amnesties to try to end a 15-year Islamic insurgency, resulting in thousands of militants turning themselves in but sparking fierce criticism from the families of victims.

Al-Qaeda's self-styled North African branch has claimed responsibility for the twin truck bombings. Victims included U.N. staff from around the world, police officers and law students.

The Interior Ministry raised the official death toll to 37, saying six more bodies were found in the rubble of the U.N. offices.

President Bush called Algerian President Abdelaziz Bouteflika yesterday to discuss the attacks and offer his condolences, White House press secretary Dana Perino said.

In a Web-site posting, al-Qaeda in Islamic North Africa described the U.N. offices as "the headquarters of the international infidels' den."

The group, also known as al-Qaeda in the Islamic Magreb, also posted photos of the two men it said were the bombers. Both posed with weapons and wore camouflage, with the younger man smiling.

The Algerian security official identified the older bomber, who struck the U.N. offices, as Chebli Brahim, who had cancer. Two of his sons had been killed in army crackdowns on extremists.

Brahim was a member of the Muslim fundamentalist party Islamic Salvation Front, or FIS. He was arrested in a sweep of FIS members after the government banned the party, the official said.

The younger bomber, who targeted Algeria's Constitutional Council building, was identified as Charef Larbi, from the poor Algiers suburb of Oued Ouchayeh, the official said. He had been arrested on the charge of "supporting terrorist groups" and imprisoned in 2004.

Upon Larbi's release last year, the official said, he went into hiding with extremists in Algeria's scrubland.