Syrian troops on Friday opened fire on opposition protesters in the eastern city of Deir el-Zour that has been under siege by government forces for several days. Activists and witnesses said Syrian forces began firing live ammunition at protesters outside a mosque in the city following Friday prayers. It was not immediately clear if there were any casualties. Earlier on Friday, Syrian security forces began carrying out raids in anticipation of the mass Friday protests. At least 16 people were killed across Syria on Thursday as the government widened its crackdown, despite mounting international condemnation of Syrian President Bashar al-Assad's use of violence against protesters. On Thursday, the U.S. Secretary of State Hillary Clinton called on Europe and China to impose additional sanctions on Syria's oil and gas industry.