The Syrian capital of Damascus has seen one of its bloodiest days in nearly two years of fighting between government forces and rebels seeking the ouster of President Bashar al-Assad. The death toll from a series of bomb blasts in the city Thursday has risen to at least 83 people, most of them civilians. The Syrian Observatory for Human Rights said more than 60 of the victims died in a blast that apparently targeted the ruling Baath Party headquarters. More than 20 more were killed by three other car bombings in a northern district, most of them soldiers, according to the group. Hundreds of people were injured in the attacks. The United Nations announced Thursday that U.N.-Arab League envoy Lakhdar Brahimi will continue attempting to broker peace in Syria, at least through the end of the year.