Two powerful blasts in quick succession have killed dozens of people and injured more than 100 others in the Syrian capital Damascus, according to Syrian officials and state media.The Syrian health ministry said at least 29 people were killed and 103 wounded in Thursday's explosions that hit the Qazaz neighbourhood, where a Syrian intelligence agency has its headquarters."Two explosions caused by terrorists took place on the road in the south of Damascus," Syrian state television said, adding that the blasts occurred "as people were heading to work and children to school".An Associated Press reporter at the scene said medical workers were collecting human remains from the streets after the explosions and heavily damaged cars and pickup trucks stood smouldering in the area.The outer wall of the nine-storey headquarters collapsed, although the structure inside appeared intact.Al Jazeera's Rula Amin, reporting from neighbouring Lebanon, said the explosions had been heard all over the city."Damascus residents from different parts of town all heard the explosions. People were really shaken by the power of these blasts. These attacks - every day - become more efficient and more deadly."Syrian TV showed dozens of mangled, burnt and smouldering vehicles, some containing incinerated human remains.A large crater could be seen in the road and at least one lorry had been overturned.One resident, who said he got within 100 metres of one of the blasts before being turned back by security forces, told Reuters news agency he saw broken glass on the street and women crying. Nearby schools had sent children home for the day.