More than 305 people were killed across Syria on Wednesday, making it the bloodiest single day of the 18-month revolt, the Syrian Observatory for Human Rights said.
"This is the highest toll in a single day since March 2011. And this is only counting those whose names have been documented. If we count the unidentified bodies, the figure will be much higher," Observatory director Rami Abdel Rahman told AFP by telephone.
A total of 199 of Wednesday's dead were civilians, the Britain-based watchdog said.
The previous highest death toll of the uprising was on July 19, when 302 people were killed, according to the Observatory.