The United States ambassador to Iraq warned Iraqi politicians on Monday they risk a loss of American support if they do not establish a genuine national unity government, saying the US will not invest its resources in institutions run by sectarians. Meanwhile, at least 24 people were killed by bombings in Baghdad and elsewhere.

A wave of car bombings shook the Iraqi capital on Wednesday, killing at least 12 people as rebels stepped up their offensive to block the January 30 national election. Other attacks were reported north and south of the capital, but the United Nations election chief said only a sustained onslaught can stop the ballot.