"The bottom line is there can be no doubt in the international community's mind that Syria has retained chemical weapon in violation of its agreement. And it stated that it had removed it all," Mattis said warning Damascus against using such weapons in the future.
On April 4, the Syrian opposition accused the Syrian army of using chemical weapons in the province of Idlib, which reportedly resulted in dozens of deaths. Damascus refuted the accusations, saying all chemical weapons had been destroyed under the supervision of the Organization for the Prohibition of Chemical Weapons (OPCW).
In response to the incident, the United States conducted missile strikes against Syria's Ash Sha’irat airbase.
"They have dispersed their aircraft, no doubt they have dispersed their aircraft in recent days," Mattis said at a press conference.
The United States launched 59 Tomahawk cruise missiles at the Sha'irat air base in Homs in response to a suspected chemical attack in the Idlib province, which the West blamed on Damascus. The Syrian government denied the accusations saying it possessed no chemical weapons.