BEIRUT, Lebanon — The U.S. military acknowledged Saturday that its warplanes had carried out an airstrike that the Syrian government said killed its troops in the eastern province of Deir el-Zour. U.S. military officials said the pilots in the attack believed they were targeting the Islamic State group.
Russia's Defense Ministry said the U.S. attack killed 62 Syrian troops, wounded 100 more and opened the way for an Islamic State offensive.
The U.S. military stopped short of admitting it had hit Syrian forces. A statement by U.S. Central Command, which is based at MacDill Air Force Base in Tampa, said planes stopped the attack after a warning from Russia that the strikes could be hitting Syrian troops.
If the episode took place as described by Syria, it would be a major error at a time of escalating tensions. It came as a partial cease-fire that started Monday continues to steadily unravel after it was declared with much fanfare by the United States and Russia.
Russia, the Syrian government's main ally, said it would call an emergency U.N. Security Council meeting to discuss the strikes.
The Syrian government was quick to insist that the strike was not a mistake. Instead, the government said it was "a very serious and flagrant aggression" that aided the Islamic State and proved its long-held assertion that the United States supports the jihadi group as part of an effort to oust President Bashar Assad.
"These attacks confirmed that the U.S. clearly supports the terrorism of Daesh," SAMA television, a state-run news outlet, said, using an Arabic acronym for the Islamic State group, which is also known as ISIS. The channel quoted a statement issued by the Syrian military's general command, which said the attack exposed "false claims of fighting terrorism" by the United States.
Central Command denied it would carry out such an airstrike on purpose.
"Coalition forces would not intentionally strike a known Syrian military unit," the statement said , offering at an unexpected moment one of the clearest statements yet of how far the United States has moved from three years ago.
In 2013, President Barack Obama threatened to strike Assad's forces in retaliation for chemical attacks on rebel-held suburbs that killed more than 1,000 people. He instead struck a deal with Russia to dismantle Assad's chemical weapons program.
"Coalition forces believed they were striking a Daesh fighting position that they had been tracking for a significant amount of time before the strike," the Pentagon said. "The coalition airstrike was halted immediately when coalition officials were informed by Russian officials that it was possible the personnel and vehicles targeted were part of the Syrian military.