A homicide truck bomb exploded on a major bridge in Baghdad early Thursday, collapsing the steel structure and sending cars toppling 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 up against twisted girders sinking into the water, as police patrol boats searched for survivors. Scuba divers donned flippers and waded in from the banks of the Tigris, as U.S. helicopters whirred overhead.

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.

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The al-Sarafiya bridge connected two northern Baghdad neighborhoods — Waziriyah, a mostly Sunni enclave, and Utafiyah, a Shiite area.

Police said the attack was by a homicide 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 bridge's steel structure were left crumbling. At the base of one of them laid 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-Sarafiyah bridge was built by the British during the 1950s to connect the two sides of Baghdad separated by the Tigris river. Trains also used to pass over the bridge, but the railway was eliminated in the early 1970s to provide more room for cars.

"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 is a duplicate of another structure in Fallujah, built later and made infamous in March 2004, when angry mobs hung the charred bodies of U.S. contractors from the bridge's girders.

Also Thursday, the U.S. military said its troops killed two suspected insurgents and captured 17 in raids across the country.

Complete coverage is available in FOXNews.com's Iraq Center.