Deputy Secretary William Burns will go to the meeting in Marrakesh in place of Clinton, who has a stomach virus, CNN reported.
"We will let you know when she shakes this bug and resumes a public schedule," State Department spokesman Philippe Reinnes said.
The Friends of Syria is an international diplomatic collective of countries and and entities that meets periodically to discuss the situation in Syria, where anti-government protesters have engaged in a bloody fight to try to oust President Bashar Assad since March 2011.
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