Moscow : Georgia's breakaway region of South Ossetia on Friday mobilised reservists and threatened to use heavy weapons against Georgian forces after two people were killed in heavy exchanges of fire overnight.

Neither Tbilisi nor the separatists admitted violating a ceasefire, blaming the hostilities on one another.

Quoting the rebel region's officials, Russia's Vesti-24 channel said Georgia had started bombarding the separatist capital Tskhinvali with mortar shells at about midnight on Thursday. "Then intensive gunfire followed," it reported.

The channel ran video footage of wounded people being operated on in a Tskhinvali hospital.

"This is a well-planned provocation staged by the Georgian side," separatist leader Eduard Kokoity said in a statement.