Local opposition activists in the city of Homs said 22 people were killed and 70 others wounded when a rocket struck the Waer neighborhood of Homs on Thursday.
The savage offensive on Waer followed a huge explosion at a munitions depot in a pro-Assad suburb. Reuters reported that 40 people were killed and at least 120 people were wounded in that blast.
The explosion occurred in the southeastern district of Wadi al-Dhahab, where the army has taken control, the Syrian Observatory for Human Rights said. The group has a network of sources in the opposition and state security forces.
Revolutionary pages via social media circulated a video of the blast, which attracted a huge number of comments. Some people described the explosion as the "new Hiroshima."
"There are mixed feelings of happiness and sadness," one activist said. "Is it God's revenge for those who are killing us and for the people who back and support Bashar al-Assad?"
The Observatory said the casualties included both soldiers and civilians and that some of the wounded were in a critical condition.
Waer and other old neighborhoods of Homs were bombarded by regime forces earlier in the morning, according to the Observatory.
There were also reports of two other explosions, killing two civilians, including a child and injuring several others.
Homs,140 kilometers north of Damascus, lies at a strategic crossing linking the capital with army bases in coastal regions dominated by Assad's Alawite sect.
Translated and edited by the Syrian Observer