Two apparently coordinated car bombings have killed six people in the northern Iraqi city of Mosul.

Police and medical officials say the blasts took place Saturday on a busy street near government buildings. They say the explosions wounded at least 55 people.

Meanwhile, government officials say gunmen stormed the home of a school teacher in a village near Tikrit, killing the teacher and four family members, including three children.

There were no immediate claims of responsibility for either incident. Violence in Iraq is down sharply from its peak in 2006 and 2007. However, a new spate of attacks has raised concerns about a possible increase in violence as the U.S. prepares to withdraw its forces at the end of the year.