Georgian authorities said South Ossetian troops had fired mortars at the village of Tamarasheni, wounding an 18-year-old man.
"Rocket-propelled grenades were launched today for one to two hours from the Ossetian village of Kverneti," Mamuka Kurashvili, commander of the Georgian forces in South Ossetia.
Tensions have spiraled in the region in the last three days, but the reports could not be independently confirmed.
Home to about 60,000 people, South Ossetia broke from Georgia amid heavy fighting after the Soviet Union's 1991 collapse.
Although its government is not recognised internationally, the separatist leadership does have support from Russia.
On Friday, Andrei Patayev, a spokesman for the separatist authorities, said Georgian forces had launched grenade attacks on Tskhinvali and said that one man had died after being wounded by Georgian snipers.
The day before, hundreds of villagers poured paint and petrol on Russian vehicles and checkpoints in protest at attempts by Russian forces to prevent the building of a new road linking ethnic Georgian settlements.
The dispute over South Ossetia is one of two separatist conflicts that are impeding efforts by Mikheil Saakashvili, the Georgian president, to integrate his country with the West and join Nato, a goal which Moscow opposes.
Georgia has recently stepped up efforts to regain control of South Ossetia, in particular with the creation in April of a so-called "temporary administration" in the region.
Tbilisi plans to sideline the separatists by conducting formal negotiations on the region's reintegration to Georgia with that administration, led by Dmitry Sanakoyev, a pro-Georgian former independence fighter.