A monitoring group says an Arab-Kurdish coalition has almost taken the whole city.
"They were fighting to defeat a truly evil enemy and to protect our homelands," the military said in a statement.
"Of all the wars I have covered in various countries, Mosul has been the worst."
A monitoring group said the death toll in Deir Ezzor was likely to increase as many of those injured were in a critical condition.
The U.S. denied Syrian army reports that a Washington-led coalition struck a cache of toxic substances used by the Islamic State group, killing "hundreds."
The 68 nations involved in the fight against ISIS were set to meet to hear for the first time President Donald Trump's plan to defeat the militant Islamic State group.
Iraqi special forces are aiming to recapture the city taken by militants in 2014.
ISIS already has affiliates elsewhere in the world.
The militant group calls the U.S. president "vile" and the "mule of the Jews."
The Nice murderer Mohamed Lahouaiej Bouhlel was inspired from abroad over social media.
The cleric is considering legal action against the defense secretary.
Critics said the mock attack in Manchester, England, risked stoking religious divisions.
The serviceman was the third American to be killed in direct combat since 2014.
The 13th Marines Expeditionary Unit has just arrived in the Gulf, a force nearly twice the size of the one it replaces. And B-52s have been moved to Qatar.