The civilians were killed in operations around the world, from Somalia to Yemen to Syria.
Contributing to the inaccurate picture of civilian deaths is the Pentagon's failure to actually investigate claims of such casualties, says Daphne Eviatar, director of security with human rights at Amnesty International USA.
Overall, between 3,923 and 6,102 non-combatants were likely killed in these 766 events in 2017- a 215% increase on the 1,243 to 1,904 civilians estimated as likely killed by Coalition strikes in 2016. According to United States Air Forces Central Command data, in 2016 there were about 31,000 air strikes in both Iraq and Syria. According to the Bureau of Investigative Journalism, between 380 and 801 civilians were killed by drone strikes alone between 2009 and 2015, as Obama ramped up the US' targeted-killing program.
The only comparable figures released by former President Barack Obama came in 2016, when he signed an executive order requiring the government to release figures for civilian casualties caused by US airstrikes meant to target combatants in non-war zones. That same program would result in the drone assassination of USA citizens in Yemen and Pakistan. The Pentagon report shrugs off civilian casualties, calling them an unavoidable effect of war.
The report said no casualties were identified as a result of USA operations in Somalia and Libya, but the numbers are subject to change due to ongoing assessment of 450 reports of civilian deaths.
"This is especially true when fighting in urban areas and against adversaries like ISIS and al-Qaeda who use civilians as shields and whose tactics include intentionally endangering the lives of innocents", it added.
The Observatory recorded 395 civilians killed across Syria last April, while it counted 400 civilian deaths in April 2011, the first full month of the conflict.
Dead civilians were citizens of Iraq, Syria, Afghanistan and Yemen.