"We've tried to convey the message in recent days that if there's a third use of chemical weapons, the response will be much stronger," US National Security Adviser John Bolton said while answering questions after a policy speech.
Bolton said an allegation that the United States is giving authorization for al-Qaeda to use chemical weapons in order to blame it on the Syria government is a very outrageous claim.
"I can say we've been in consultations with the British and the French who have joined us in the second strike and they also agree that another use of chemical weapons will result in a much stronger response," he noted.
On August 22 Bolton also stated that the US would respond "in a swift and appropriate manner to any verified chemical weapons use in Idlib or elsewhere in Syria."
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Though the Syrian forces regained control of the biggest part of the country, the Idlib province is in one of Syria's de-escalation zones and remains an important stronghold for terrorists.