US Secretary of State John Kerry stated that the coalition forces bombing Syrian troops during a ceasefire led to "the thing [falling] apart" at a Washington forum in the US capital, Tuesday.
In September 2016, after a truce had been brokered, the United States carried out airstrikes near the Deir ez-Zor airport, which left dozens of Syrian soldiers killed or injured.
Washington has always maintained that it was an unintentional mistake, but the Syrian government accused them of targetting its troops intentionally.
Comment: See also: Russia-brokered ceasefire shattered as US airstrikes against Syrian Army in Deir ez-Zor leaves 80 soldiers dead, over 100 injured (UPDATES)