At least 85 people have been killed and 110 wounded in three apparently coordinated car bomb attacks in Balad, north of Baghdad.

Three car bombs went off within minutes of each other in a predominantly Shi'ite district in the mixed Shia and Sunni town, about 90 km north of the capital.

Two cars blew up in the town's main shopping street at around 6.30pm local time, with a third vehicle exploding in a market in another neighbourhood 10 minutes later.

According to Iraqi officials, 35 women and 22 children were among those killed.

A fourth car bomb exploded an hour later in Baghdad as an Iraqi army convoy was passing by, but there were no immediate reports of casualties.

Earlier, five US soldiers were killed in a bomb explosion in Ramadi, 110 km west of Baghdad.

The deaths bring to 1,919 the number of US military personnel killed in Iraq since the US-led invasion of March 2003.

Ramadi has been a focus of insurgent activity over the past two years.