At least 801 civilians have been killed by U.S.-led coalition airstrikes against the Daesh terrorist group in Iraq and Syria, according to a Pentagon report released Thursday. Five more strikes, all in Syria, were investigated over the past month and found to have resulted in 15 civilian additional civilian deaths, the report stated. However, monitoring groups say the number of civilian casualties from coalition airstrikes in the fight against Daesh is far higher than the Pentagon acknowledges.

Since August 2014, more than 5,000 civilians have been killed as a result of coalition airstrikes in Iraq and Syria, according to the London-based Airwars organization that tracks civilian deaths in the anti-Daesh operation.

The majority of civilian casualty allegations are currently from coalition airstrikes in Syria. The Pentagon says they are still assessing 695 reports of civilian casualties, more than 400 of which are from strikes carried out in Syria.

The U.S.-backed Syrian Democratic Forces (SDF), which is predominantly led by the PKK 's Syrian affiliate, the People's Protection Units (YPG) retook the city of Raqqa from Daesh control in October and pushed Daesh fighters out of a swath of territory along the Euphrates river valley in the following weeks.

Each investigation that found an allegation credible determined it was "more likely than not" that a coalition strike resulted in a civilian casualty, the report stated.

U.S.-led coalition airstrikes are credited with fueling advances against Daesh by Iraqi and Syrian ground forces. Since the coalition's campaign of airstrikes against Daesh was launched in August 2014, Daesh-held territory has been reduced to pockets of desert along the Iraqi-Syrian border.

Meanwhile, over 400 U.S. Marines involved in the fight against Daesh in Syria are being withdrawn after allied forces ousted the jihadists from Raqqa, the U.S.-led coalition said yesterday, according to AFP.

"With the city liberated and [Daesh] on the run, the unit has been ordered home. Its replacements have been called off," the coalition said in a statement.