“That might be true if Barzeh was filled with difficult-to-replace equipment or if crucial personnel were killed in the strike,” he said. “But what we see is just a building. Are we certain all the important bits were above ground and destroyed in the airstrike?”
In November, the Organization for the Prohibition of Chemical Weapons inspected Barzeh and collected samples for testing. It concluded last month that inspectors “did not observe any activities inconsistent” with Syria’s obligations under the Chemical Weapons Convention.
Defense Secretary Jim Mattis said chlorine gas was among the weapons used in the April 7 suspected attack on Douma, outside Damascus. But he provided little evidence, nor any that the three targets contained chemical agents banned by a 2013 agreement between Russia and the United States to eliminate Syria’s chemical weapons program.
Chlorine, which is commonly used in industrial products, was not outlawed as part of the 2013 agreement. However, it is described by the Organization for the Prohibition of Chemical Weapons as a choking agent, and is prohibited when used as a weapon; Syria is believed to have used it in several chemical attacks since 2013.
The organization’s inspectors have sought to gain access to Douma to collect evidence of chemical agents but were forced to turn back after coming under gunfire this week. Russian state news media reported that the Russian military found a rebel chemical lab in the same area.
Mr. Mattis on Wednesday blamed the Syrian government for the holdup. And on Thursday, the State Department accused Russia of helping Mr. Assad’s government “sanitize” Douma of evidence of a chemical attack.
At the United Nations, Russia maintained that the April 7 attack was a hoax fabricated by Mr. Assad’s enemies. It distributed a nearly four-minute video that featured an interview with a young boy from Douma who, it said, was made to appear, falsely, as a victim of a chemical weapons attack in a staged hospital emergency scene.