Thousands of Syrians once again defied a government crackdown on Friday to call for the overthrow of President Bashar al-Assad. Lending their voice to the weeks-long protests, the exiled Muslim Brotherhood called on Syrians to join in demonstrations against Assad. It was the first time that the Brotherhood, which was crushed along with secular leftists under the rule of late President Hafez al-Assad, had thrown its weight behind the demonstrations. In Daraa, where protests erupted weeks ago when the several teens were arrested for drawing graffiti, Syrian soldiers fired into the air to prevent people attending Friday prayers. Also in Daraa, Syria's official state news agency said that an “armed terrorist group” attacked a checkpoint, killing four soldiers and kidnapping two. One resident told Al Jazeera that “snipers are on rooftops of buildings firing at anything that moves.” Another witness said security forces armed with machine guns patrolled the circular road around Damascus. Meanwhile, the European Union is meeting today to discuss the possibility of imposing sanctions against Syria in condemnation of the crackdown that has killed at least 500 people so far.