The military intelligence report, put out less than three days after the attack, said the allied airstrikes likely set back Mr. Assad’s production of sarin gas.

But it found that the Syrian president is expected to continue researching and developing chemical weapons for potential future use, according to an American intelligence analyst who has seen the document and described it to The New York Times on the condition of anonymity…

The other two sites — the Him Shinshar chemical weapons bunker and storage facility in Homs — were severely damaged. But the analyst said the report cited surveillance assets that watched a five-ton truck leave one of those sites, the day before it was struck, with a tarp-covered load that could have included equipment or chemical weapons.