Violence killed at least 42 people Tuesday, including 16 bus passengers caught in a roadside bombing in southern Iraq, after the deadliest day for US troops in precisely six months.

The US military announced that three American soldiers were killed in a roadside bombing north of Baghdad on Monday, bringing to eight the number of troops who died that day. The last time so many US military personnel were killed in Iraq was September 10, when 10 died.

A bus that was hit by a roadside bomb is towed away near Nasiriyah, about 320 kilometers (200 miles) southeast of Baghdad, Iraq, Tuesday, March, 11, 2008. At least 16 civilians aboard died and another 22 were wounded in the blast. [Agencies]