Six car bombs exploded in Shiite-majority areas of Baghdad on Sunday, killing at least 16 people and pushing the October death toll for Iraqi violence past 600, officials said.

The blasts, which hit five different areas of the Iraqi capital, also wounded more than 50 people, security and medical officials said.

In the deadliest attack, two car bombs exploded in a commercial area in the north Baghdad neighbourhood of Shaab, killing at least five people and wounding at least 17.

Sunni militants often carry out attacks targeting members of Iraq's Shiite majority, whom they consider apostates.

Violence in Iraq has reached a level not seen since 2008, when the country was just emerging from a brutal sectarian conflict.

And the surge in bloodshed this year, which has included sectarian attacks, has raised fears Iraq may relapse into the intense Sunni-Shiite conflict that peaked in 2006-2007 and killed tens of thousands.

More than 600 people have now been killed so far this month, and more than 5,300 since the beginning of the year, according to AFP figures based on security and medical sources.

A study released this month by academics based in the United States, Canada and Iraq said nearly half a million people have died from war-related causes in Iraq since the US-led invasion of 2003.