WASHINGTON (Reuters) - U.S. officials on Wednesday rejected Russia’s claim that scores of Syrian civilians died in the explosion of a rebel chemical weapons depot hit by Syrian government aircraft.

“That strains credulity,” said one U.S. official, speaking on condition of anonymity. “Russian assertions do not comport with reality.”

A second U.S. official, who also requested anonymity, dismissed the possibility that poison gas that came from what he called “a nonexistent rebel stockpile.”