Gunmen in Iraq disguised as police officers have shot dead five Shi'ite elementary school teachers and their driver south of Baghdad.

Police say the victims were pulled from a mini-bus Monday as they were leaving the school near Iskandariyah. They were then forced back into a classroom, lined up against the wall and shot to death.

In Baghdad, authorities say at least 10 people were killed and at least 30 others wounded in a suicide car bombing near the oil ministry.

Separately, the U.S. military says three American soldiers were killed today in roadside bomb attacks. Two of the soldiers died in western Baghdad, the third was killed 80 kilometers southeast of the capital.

Meanwhile, the U.S military has released 500 detainees from Abu Ghraib prison to mark the upcoming Muslim holy month of Ramadan. Officials say another 500 prisoners will be freed over the next week.

Some information for this report provided by Reuters, AP and AFP.