This image taken from television via AP Television News shows a man and a woman leaving the area through thick dust following an explosion in the Iraqi parliament cafeteria. A suspected suicide bomber blew himself up Thursday in the cafeteria, killing at least eight people and wounding dozens in the heart of the heavily fortified, U.S.-protected Green Zone.

Baghdad, Iraq ? A suicide bomber slipped through the tightest security net in Baghdad and blew himself up Thursday in the midst of lawmakers having lunch in the parliament dining hall. U.S. officials said eight people, including parliament members, were killed in the deadliest-ever attack in the American-guarded Green Zone.

The stunning breach of security, on the same day that a massive bombing destroyed one of Baghdad’s main bridges, laid a cloud of heavy doubt about progress in the latest U.S.-Iraqi bid to clamp off violence in the capital. The drive has put thousands of troops on the streets in a massive operation to round up militants and their weapons.

A news video camera captured the moment of the blast, about 2:30 p.m. – a flash and an orange ball of fire causing Jalaluddin al-Saghir, a startled parliament member who was being interviewed, to duck. Smoke and dust billowed through the area, and confused and frightened lawmakers and others could be heard screaming for help and to find colleagues. Al-Saghir reportedly escaped injury.

But a woman was shown kneeling over what appeared to be a wounded or dead man near a table and chairs. The camera then focused on a bloody, severed leg – apparently that of the suicide bomber. At least two lawmakers were among the dead.

Three miles north and seven hours earlier, a bombing sent a major bridge linking east and west Baghdad plunging into the Tigris River. Several cars plummeted into the murky, brown water, and at least 10 people were known to have died. Many more were believed missing.

Police blamed a suicide truck bomber for the attack on the al-Sarafiya bridge, which the British built in the 1950s. AP Television News video, however, showed the bridge broken in two places – perhaps the result of two blasts.

Security officials at Iraq’s parliament said they thought the bomber in the cafeteria attack was a bodyguard of a Sunni lawmaker who was not among the casualties. The bombing, which wounded both Sunnis and Shiites, showed that determined suicide assailants remain capable of striking at will.

U.S. military spokesman Maj. Gen. William Caldwell said the attack bore the trademarks of al-Qaida in Iraq. The terrorist group is fighting not only to oust U.S. forces from Iraq but also against fellow Sunnis in the western part of the country who have begun to leave the insurgency and side with U.S. and Iraqi soldiers.

Sunni targets

One of the lawmakers killed in the attack, Mohammed Awad, was a member of the moderate Sunni National Dialogue Front, according to party leader Saleh al-Mutlaq. A female Sunni lawmaker from the same list was wounded, he said.

A second Sunni lawmaker known to have been killed was Taha al-Liheibi, a key go-between in government efforts to negotiate with Sunni insurgents about putting down their arms and joining the political process.

Niamah al-Mayahi, a member of the Shiite United Iraqi Alliance bloc, initially was reported killed by Saleh al-Aujaili, a fellow member of the bloc. Later, al-Dabbagh’s office said al-Mayahi was gravely wounded, but it was not immediately possible to reconcile the reports.

The parliament security officials, who spoke Thursday on condition of anonymity because they were not authorized to release the information, said two satchel bombs also were found in the parliament building near the dining hall. A U.S. military bomb squad took the explosives away and detonated them without incident, the officials said.

U.S. reaction

President Bush strongly condemned the attack, saying: “My message to the Iraqi government is ‘We stand with you.'”

“It reminds us, though, that there is an enemy willing to bomb innocent people in a symbol of democracy,” he said.

But congressional Democrats said the attack was evidence that substantial progress was not being made in the war.

“How the president and people around him can say things are going well is really hard to comprehend,” said Senate Majority Leader Harry Reid.

Congress has passed bills that would force the Bush administration to set a timetable for withdrawing American troops. Bush has said he would veto any such measure and that American forces need more time to curb the raging violence.

Hours after the bombing, Iraqi officials, including Deputy Prime Minister Barham Saleh, met with the commander of U.S. forces in Iraq, Gen. David Petraeus, and decided to put the Interior Ministry in charge of security at parliament, government spokesman Ali al-Dabbagh said. The building previously was guarded by a private security company, he said.