"(The Department of Defense) assesses that there are credible reports of approximately 499 civilians killed and approximately 169 civilians injured during 2017" as a result of military operations in Iraq and Syria targeting ISIS, operations in Afghanistan targeting the Taliban and ISIS, and operations in Yemen against al Qaeda in the Arabian Peninsula and ISIS, the report said.

The report which provides an estimate of the number of civilian casualties in counterterrorism operations in 2017 also said the Defense Department has "no credible reports" of civilian casualties as a result of US military operations in Somalia or Libya last year.