.jpg "Syria`s Assad says US has no proof of chemical weapons use")
US Secretary of State John Kerry has been lobbying hard for military action against Mr Assad during talks with EU and Arab foreign ministers in Europe.
US Congress is due to debate whether to authorise intervention in Syria.
Lawmakers will return from their summer recess on Monday to start discussing President Barack Obama`s resolution to launch a "limited, narrow" strike.
Both the Senate and House of Representatives could vote on the issue as early as Wednesday.
The US accuses Mr Assad`s forces of killing 1,429 people in a sarin gas attack on 21 August on the outskirts of the capital, Damascus.
Mr Assad`s government blames the attack on rebels fighting to overthrow him in the country`s two-and-a-half-year civil war, which has claimed some 100,000 lives, according to UN estimates.
Meanwhile there are reports that rebel forces have taken control of the historic Christian town of Maaloula, north of Damascus.
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