A car bomb exploded near a passing US military patrol in Baghdad on Saturday, killing four passers-by and wounding four others, Iraq's Interior Ministry said, but the US patrol escaped unharmed.
The bomb went off in Qahtan Square, a busy intersection of western Baghdad where there is a constant flow of traffic. Police said they believed the attack was carried out by a suicide bomber but that could not be confirmed.
There has been a surge in car bombs and suicide attacks by the Sunni Arab-led insurgency over the past week, leading to the deaths of more than 200 people, the vast majority civilians.
Many of the attacks have targeted the Shia community, aggravating Iraq's sectarian conflict and pushing the country to the brink of full-blown civil war. The violence comes in the run-up to elections on December 15, when voters will chose the country's first four-year parliament since Saddam Hussein was overthrown in 2003.