BBC News reports: About half a million people died in Iraq as a result of war-related causes between the US-led invasion in 2003 and mid-2011, an academic study suggests.

University researchers from the US, Canada and Iraq based their estimate on randomised surveys of 2,000 households.

The toll includes not only violent deaths from the invasion and subsequent insurgency, but avoidable fatalities linked to infrastructure collapse.

It exceeds the 112,000 violent civilian deaths reported by Iraq Body Count.

The British-based organisation bases its tally on media reports, hospital and mortuary records, and information from official and non-governmental sources.

There has been a surge in sectarian violence in Iraq in the past year, with almost 5,000 civilians killed in attacks between January and September, according the UN. It says more than 3,000 people died in 2012.