The opposition Syrian National Council said on Sunday that the army was hitting key public institutions in its bombardment of rebel fighters in commercial capital Aleppo, some of historical significance.
"After failing to subdue (rebel forces) in Aleppo... the Syrian regime's gangs have started to target government institutions and buildings," the exiled opposition group said in a statement.
"Some of them have historical and archaeological value."
Aleppo preserves a raft of historical sites, including its renowned 13th century citadel. The UN Educational, Scientific and Cultural Organisation named the Ancient City a World Heritage Site in 1986, citing its "outstanding universal value."
The SNC accused the army of shelling Aleppo's television building.
"The criminal regime does not hesitate to shell these institutions," the group said, adding: "The rebels were forced to move away from the television building in order to protect the Syrian people's property and heritage."
In the same statement, the SNC renewed its appeal for 800 families trapped under siege by the army for more than 60 days in rebel-held neighbourhoods of the central city of Homs.
"There are 800 families threatened not only by savage shelling, but also by hunger, thirst, a lack of medicines," the group said.
The SNC "calls on the international community and neighbouring countries to deal seriously with the threat posed by the regime to the existence of Syria and international peace and stability," it added.