The president of Georgia's breakaway region of South Ossetia reported "hundreds of civilians" killed in the separatist capital under siege by Georgian troops Friday, reported dpa, refer to news agency Interfax.
Calling the fighting a "genocide," President Eduard Kokoity said "hundreds of peaceful inhabitants were lost in Tskhinvali."
"These last tragic events should become the last step toward recognition of South Ossetia's independence," he added.
Moscow deployed troops to support its ally South Ossetia on Friday, in what has threatened to become a full-fledged war with its neighbour Georgia.
At least 10 Russian peacekeepers were killed as heavy fighting raged in South Ossetia, Interfax had earlier reported.
Despite television images of wounded Georgian soldiers in local hospitals, there has been no official confirmation of casualties.
Georgian President Mikheil Saakashvili said troops now controlled a "large part of South Ossetia" and have "liberated" Tskhinvali.