"A military report warned that striking the giant structure could cause tens of thousands of deaths."
"Near the height of the war against the Islamic State in Syria, a sudden riot of explosions rocked the country’s largest dam, a towering, 18-story structure on the Euphrates River that held back a 25-mile-long reservoir above a valley where hundreds of thousands of people lived.
The Tabqa Dam was a strategic linchpin and the Islamic State controlled it. The explosions on March 26, 2017, knocked dam workers to the ground and everything went dark. Witnesses say one bomb punched down five floors. A fire spread, and crucial equipment failed. The mighty flow of the Euphrates River suddenly had no way through, the reservoir began to rise, and local authorities used loudspeakers to warn people downstream to flee.
The Islamic State, the Syrian government and Russia blamed the United States, but the dam was on the U.S. military’s “no-strike list” of protected civilian sites and the commander of the U.S. offensive at the time, then-Lt. Gen. Stephen J. Townsend, said allegations of U.S. involvement were based on “crazy reporting.”"
Dave Philipps, Azmat Khan and Eric Schmitt report for the New York Times January 20, 2022.