Iraqi officials say two car bombs have exploded in Diwaniyah, killing at least 22 people and wounding 30 others.

Authorities said the attack happened Tuesday at a police checkpoint outside a local governor's house in Diwaniyah, which is located about 150 kilometers south of the capital, Baghdad.

The governor, Salim Hussein Alwan, was not harmed.

Officials said at least one suicide bomber was involved in the attack, which was one of several deadly bombings across Iraq on Tuesday. Elsewhere, including the capital, Baghdad, blasts killed at least four people and wounded 16 others.

Violence in Iraq is down sharply from its peak in 2006 and 2007. However, a new spate of attacks, including several against government officials, has raised concerns about a possible increase in violence as the U.S. prepares to withdraw its forces at the end of the year.