Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Heightened Security in Syria Ahead of Planned Protests VOA News May 06, 2011 Syrian activists say security forces have taken up positions in cities across the country, as opposition leaders urge demonstrators to return to the streets on Friday for what they are calling "Day of Defiance" protests. Opposition leaders have called for protesters to rally after Friday prayers, in spite of a government crackdown on demonstrations. On Thursday, residents said troops and armored vehicles had deployed into cities including Homs, Banias and Rastan. However, the army said it has begun withdrawing its forces from the besieged town of Daraa, the epicenter of protests against President Bashar al-Assad. The military said Thursday it had "carried out its mission in detaining terrorists" in Daraa and had restored calm in the city. But residents said tanks, troops and snipers were still restricting their movement. Rights groups say at least 600 people have been killed in Syria's crackdown on nationwide anti-government unrest and as many as 8,000 are missing or have been detained. Anti-government protests that began as calls for reform have developed into demands for the ouster of President Assad. Some information for this report was provided by AP. Follow our Middle East reports on [1]Twitter and discuss them on our [2]Facebook page. References 1. http://twitter.com/VOAMiddleEast 2. http://www.facebook.com/pages/VOAMiddleEastVoices/124360240958667?%20%20%20%20v=wall .