A suicide truck bomber struck a strategic bridge outside Baghdad on Tuesday, sending vehicles plunging into the river and killing at least 10 people in the second attack on the span in three months, police said. The attack came as 16,000 US and Iraqi troops began a new operation north of the Iraqi capital targeting insurgents who have fled a crackdown in the restive city of Baqouba, the military said Tuesday. On the political front, leaders of Iraq's divided factions held a flurry of meetings in preparation for a crisis council planned by Prime Minister Nouri al-Maliki as he seeks to save his crumbling government, which faces allegations of a Shiite bias. "I think that the circumstances require us to do our best to bring the country out of this difficult situation," Iraq's Sunni Vice President Tariq Hashemi told reporters after holding talks with Kurdish leader Massoud Barzani, who traveled from his autonomous northern region to Baghdad this week to help broker a compromise . The Thiraa Dijla bridge in Taji, a town near a US air base some 20 kilometers north of the capital, came under attack around noon, police said, giving the casualty toll. The bridge, which stretched across a canal on the main highway that links Baghdad with the northern city of Mosul, was bombed three months ago and only one lane had reopened, according to the police officials, who spoke on condition of anonymity because they were not authorized to release the information. The attacker detonated his payload in the middle of the bridge after avoiding an Iraqi army checkpoint that was only monitoring traffic going the other direction, a police officer said, adding that 40 meters of the bridge had collapsed. Rescue crews were trying to recover bodies trapped inside three minibuses and the truck that had fallen into the canal, which links the Tigris and the Euphrates rivers, the officials said. US and Iraqi troops cordoned off the area to evacuate the wounded, the military said, without providing a casualty toll. The US and Iraq operation farther north of the capital, dubbed Operation Lightning Hammer, began late Monday with an air assault and was part of a broader US push announced Monday to build on successes in Baghdad and surrounding areas by targeting al-Qaida in Iraq and Iranian-allied Shiite militia fighters nationwide. Maj. Gen. Benjamin Mixon, commander of US forces in northern Iraq, said the troops were pursuing al-Qaida cells that had been disrupted and forced into hiding by previous operations. "Our main goal with Lightning Hammer is to eliminate the terrorist organizations ... and show them that they truly have no safe haven - especially in Diyala," he said in a statement. Four more US soldiers were reported killed in separate attacks - three in an explosion near their vehicle Monday in the northwestern Ninevah province and another who was died of wounds sustained during combat operations in western Baghdad. A US transport helicopter also went down Tuesday near the Taqaddum air base, west of Baghdad, the military said. The CH-47 Chinook helicopter was conducting a routine post-maintenance test flight when it went down in Anbar province, Marine spokesman 1st Lt. Shawn Mercer said, adding the site had been sealed off and the cause was being investigated. He gave no immediate information about how many people were on the helicopter or their status. Local officials, meanwhile, said four civilians, including a young girl, were killed and five wounded Tuesday during a raid by joint US-Iraqi forces in Baghdad's Shiite district of Sadr City. The US military said four gunmen were killed and eight detained after a fierce gunfight, but it had no reports of civilian deaths. Associated Press photos showed the body of 6-year-old Zahraa Hussein lying in a wooden coffin, her white nightdress stained with blood. A police official, who spoke on condition of anonymity because he was not authorized to release the information, said the girl and her father had been struck by shrapnel while they slept on the roof of their house seeking relief from the heat. Spokesman Lt. Col. Christopher Garver said he had no reports of civilians killed in the operation: "We work very hard to avoid any injury to civilians." The troops raided three buildings in search of a rogue Shiite militia leader suspected of coordinating and conducting attacks against US-led forces and moderate Iraqis, the military said in a statement. As the armored vehicles were leaving, they were attacked by two roadside bombs and small-arms fire, prompting helicopters to fire warning shots to allow the convoy to escape the attack, it said, adding that US-led ground forces also returned fire. Al-Maliki has struggled over the past days to pull together a meeting of Iraq's main religious and ethnic groups, which had been expected as early as Tuesday. Instead, Iraqi President Jalal Talabani hosted a luncheon meeting at his residence in Baghdad, pulling together about 50 members of various political groups for informal discussions about the political crisis facing the Shiite-dominated government. Talabani said discussions would continue. "Today's meeting was very friendly and was paving the way for meetings tomorrow morning," he said. Al-Hashemi did not attend Talabani's luncheon but said he was still engaged in the political process. "We are determined to hold the summit meeting in the near future, but there are some procedural issues that we should agree on," he said. Another influential Sunni leader, Adnan al-Dulaimi, who has been outspoken in recent days against al-Maliki's government, attended the luncheon and sounded conciliatory afterward. "We will attend any meeting we are invited to. We will seek the national reconciliation," he told reporters. He said there had been an agreement on releasing some detainees, but did not elaborate. Al-Maliki's government - a shaky coalition of Shiites, Sunnis and Kurds - has been gutted by boycotts and defections. A full-scale disintegration could touch off power grabs on all sides and seriously complicate US-led efforts to stabilize Iraq.