Syrian government forces are being accused of committing what could be the deadliest massacre of Syria’s 17-month-old conflict to date. On Saturday, activist groups said more than 300 bodies were found in homes around Darayya, most of them showing signs of “execution-style” murder. Unverified video shows rows of bodies, including those of children, bloodied and wrapped in sheets. The killings occurred as the Syrian regime retook control of Darayya after three days of fighting. The regime has denied responsibility and accused rebel forces of carrying out the massacre. Overall, activists say more than 400 people were killed across Syria on Saturday — the country’s bloodiest day since the conflict began. Dozens more were killed in violence on Sunday. Earlier today, rebel forces claimed responsibility for downing a Syrian military helicopter over Damascus.