US confirms additional 50 civilian deaths in Iraq, Syria

That raises the total number of civilians assessed to have been 'unintentionally killed' by the coalition since August 2014 to 735.

In its monthly update on civilian casualties in the war against the Islamic State group, the coalition said that in August it completed its assessment of 185 reports of civilian casualties, including from previous months.

Of the 185, only 14 were deemed credible, resulting in 50 deaths. The most recent fatalities happened July 14 when 10 civilians were killed in a strike on an IS tunnel system in Mosul, Iraq.

In each case, the military said all feasible precautions had been taken to avoid harming civilians.

The US claims are seriously disputed by monitoring groups and non-governmental organisations who say the coalition under-reports civilian deaths.

Airwars, a journalist collective based in London that compiles data from public sources, estimated in June more than 3,800 non-combatants were killed since the operations began in August 2014.