Rebels are threatening more attacks. They say Wednesday's bombing represents the beginning of the end of President Bashar al-Assad's government.
The blast killed Defense Minister Daoud Rajha and Mr. Assad's brother-in-law, Deputy Defense Minister Minister Assef Shawkat. A Syrian general also was killed.
Some reports say a bodyguard carried out the attack while others say the bomb was planted in a briefcase.
U.S. President Barack Obama talked about Syria in a telephone call with Russian President Vladimir Putin. They noted the differences both sides have on Syria, but also their shared goal of ending the violence.
Syrian forces and rebels clashed again Wednesday in Damascus. About 100 people were reported killed across the country. VoA.