Four separate roadside bomb attacks killed at least 19 people in Baghdad on Tuesday (August 8, 2006), police sources said, as U.S. troops made new efforts to try to rid the capital of powerful militias and defeat insurgents. The deadliest bombing killed at least 10 people and wounded 69 in the al-Shorja market in central Baghdad. Earlier, two blasts targeting police and another aimed at one of Baghdad's busiest bus stations killed nine people, the police sources said. Eight people were wounded in those attacks. The United States has boosted its troop levels in the Iraqi capital to try to stop insurgent and sectarian violence, which has raised fears of full-blown civil war, from escalating. But the campaign is likely to hit political minefields. Prime Minister Nuri al-Maliki's government has vowed to confront militias blamed for fanning tensions, but must tread carefully as some of the armed groups have close ties to political parties, including ones in his own ruling Alliance. The U.S. ambassador to Iraq, Zalmay Khalilzad, said efforts were under way to end sectarian bloodletting. It will not be easy. Violence claims around 100 lives every day and is sapping confidence in the new government. In further lawlessness, gunmen stormed a bank in Baghdad's northern Adhamiya district and killed at least five people before walking away with the equivalent of $4,000.