The US-led coalition fighting the Islamic State in Syria and Iraq acknowledged on Wednesday the deaths of another 14 civilians, increasing the overall toll of non-fighters killed to at least 855.

The coalition said in a statement that it had completed a review in February of 84 reports of potential civilian casualties from air and artillery strikes, of which all but six were deemed not credible.

These six instances occurred in Syria between May 2017 and January 2018. In one case, five civilians were killed near Albu Kamal during a coalition strike against an Islamic State leader.

“The investigation assessed that although all feasible precautions were taken and the decision to strike complied with the law of armed conflict, unintended civilian casualties unfortunately occurred,” officials said in a statement.

Investigators were still looking at another 522 reports from the campaign. The coalition conducted a total of 29,225 strikes between August 2014 and the end of February 2018 in Iraq and Syria.

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 6,238 civilians have been killed.