Over 20 people, including eight US soldiers, were killed in insurgent attacks spread over two days across Iraq against military and Shiite targets.

On Tuesday, three US soldiers were killed when a bomb exploded as their convoy drove by. A fourth was killed half-an-hour later when unidentified gunmen shot him from a passing car, sources said.

Four US soldiers were killed in a bombing on Monday near Haswa, about 50 kilometres south of Baghdad, a defence release said.

Apart from these, at least 20 Iraqi civilians were killed in various incidents.

"These attacks were blind violence against civilians," Leith Kubba, spokesman for the new Prime Minister Ibrahim Jaafari, told the media.