( AP ) - A bomb rocked Iraq's parliament building in the heavily fortified Green Zone Thursday, killing at least two lawmakers in a stunning security breach in the third month of a U.S.-Iraqi crackdown on violence in the capital, officials said.
At least four other people were wounded in the blast, which shook a cafeteria while several lawmakers were eating lunch, initial media reports said.
Mohammed Awad, a member of the Sunni National Dialogue Front, was killed in the blast, said Saleh al-Mutlaq, the leader of the party, which holds 11 seats in Iraq's legislature. Another female Sunni lawmaker from the same list was wounded, he said.
A security official at the parliament building said a second lawmaker, a Shiite member, also was killed. He spoke on condition of anonymity because he was not authorized to speak to the media.
Apparently concerned that an attack might take place, security officials at the parliament were using sniffer dogs earlier Thursday as people entered the building - a rare precaution.
A spokesman for the U.S. Embassy in Baghdad, which is also in the Green Zone, said no Americans were injured in the blast.
"We are aware of reports of an explosion in the Green Zone. We are investigating the nature and source of the explosion," spokesman Lou Fintor said. "No Embassy employees or U.S. citizens were affected."
The attack came hours after a suicide truck bomb exploded on a major bridge in Baghdad, collapsing the steel structure and sending cars tumbling into the Tigris River below, police and witnesses said. At least 10 people were killed.
Hospital officials said another 26 were injured, and police were trying to rescue as many as 20 people whose cars plummeted off the al-Sarafiya bridge.
Waves lapped against twisted girders, as patrol boats searched for survivors while U.S. helicopters whirred overhead. Scuba divers donned flippers and waded in from the riverbanks.
Farhan al-Sudani, a 34-year-old Shiite businessman who lives near the bridge, said the blast woke him at dawn.
"A huge explosion shook our house and I thought it would demolish our house. Me and my wife jumped immediately from our bed, grabbed our three kids and took them outside," he said.
The al-Sarafiya bridge connected two northern Baghdad neighborhoods - Waziriyah, a mostly Sunni enclave, and Utafiyah, a Shiite area.
Police blamed the attack on a suicide truck bomber, but Associated Press Television News footage showed the bridge broken apart in two places - perhaps the result of two blasts.
Cement pilings that support the steel structure were left crumbling. At the base of one lay a charred vehicle engine, believed to be that of the truck bomb.
"We were astonished more when we saw the extent of damage," said Ahmed Abdul-Karim, 45, who also lives near the bridge. "I was standing in my garden and I saw the smoke and flying debris."
Locals said the al-Sarafiya bridge is believed to be at least 75 years old, built by the British in the early part of the 20th century.
"It is one of Baghdad's monuments. This is really damaging for Iraq. We are losing a lot of our history every day," Abdul-Karim said.
The al-Sarafiya bridge has a duplicate in Fallujah that was built later and made infamous in March 2004, when angry mobs hung the charred bodies of U.S. contractors from the bridge's girders.
"This bridge is linked to Baghdad's modern history - it is one of our famous monuments," said Haider Ghazala, a 52-year-old Iraqi architect.
"Attacking this bridge affects the morale of Iraqis and especially Baghdad residents who feel proud of this bridge. They (insurgents) want to demolish everything that connects the people with this land," he said.
Before the al-Sarafiyah bridge was destroyed, nine spans across the Tigris linked western and eastern Baghdad.
The river now serves as a de facto dividing line between the mostly Shiite east and the largely Sunni west of the city, a reality of more than a year of sectarian fighting that has forced Sunnis to flee neighborhoods where they were a minority and likewise for Shiites.
Baghdad's neighborhoods had been very mixed before the war but hundreds of thousands of people have been displaced since then as militants from both Muslim sects have sought to cleanse their neighborhoods of rivals.
There have been unconfirmed reports for months that Sunni insurgents and al-Qaida in Iraq were planning a campaign to blow up the city's bridges. U.S. military headquarters near the Baghdad airport and the Green Zone, site of the U.S. Embassy and Iraqi parliament and government, are both on the west side of the river.
Also Thursday, the U.S. military said its troops killed two suspected insurgents and captured 17 in raids across the country.