"I speak on behalf of all coalition service members, from privates to our most senior leaders, when I say that such tragic occurrences are deeply felt throughout our ranks and push us all to do all we can to minimize these incidents," British Army Major General Felix Gedney, a deputy commander for the coalition, told Pentagon reporters.

Officials last week said at least 1,059 civilians have been killed in coalition operations since the war against IS began in late 2014.

The new toll includes a strike on a supposed IS position in a residential part of Raqa, Syria on August 20 last year, when 33 civilians were unintentionally killed.

"The coalition makes every effort to avoid civilian deaths ... but the reality of the fight against ISIS and the brutality of this enemy has made it impossible to avoid a risk to the civilian population in the areas being liberated," Gedney said.

A total of 234 civilian casualty reports are still being reviewed by the coalition.

Monitoring group Airwars says the number of civilian deaths acknowledged by the US-led coalition is well below the true toll of the bombing campaign, estimating that at least 6,488 civilians have been killed.

The US-led operations to fight IS in Iraq and Syria have largely wound down, with the jihadists ousted from all but one small pocket in eastern Syria.