Syrian forces have fired on demonstrators taking part in a massive “day of defiance” against President Bashar al-Assad. Thousands of people have reportedly taken to the streets, defying a massive deployment of Syrian forces nationwide. More than 500 Syrians have reportedly been killed and up to 8,000 arrested since protests began in March—at least 1,000 apparently in the last week alone. Around 300 people were reportedly arrested in the Damascus suburb of Saqba on Thursday in house-to-house raids. Syrian troops, meanwhile, have begun withdrawing from the southern city of Daraa after a more-than-a-week-long siege.