BEIRUT – Syria’s main opposition groups rejected Sunday a new international plan that calls for a transitional government because the compromise agreement did not bar President Bashar Assad from participating.

Their reaction held out little hope for an end to more than 15 months of carnage on a day when the main opposition group said 800 people were killed in violence in the past week alone.

Opposition activist groups said more than 14,000 people have been killed since the uprising against Assad’s authoritarian rule began in March 2011, or on average about 900 a month.