(Adds more details, quotes)

WASHINGTON, Aug 13 (Reuters) - U.S. Secretary of State Condoleezza Rice, who leaves for Tbilisi later on Wednesday, said that Russia faced deeper isolation if it violated a France-brokered ceasefire with Georgia.

"If indeed Russia is violating a ceasefire, and I have to say the reports are not encouraging about Russia's respect for the ceasefire ... that will only serve to deepen the isolation to which Russia is moving," said Rice, adding that Russia had "seriously overreached" in its response.

Georgia last week sent forces to retake South Ossetia, a pro-Russian province that threw off Georgian rule in the 1990s. Moscow responded by sending troops.

Russia and Georgia agreed to a ceasefire but reports persisted that Moscow was still conducting military assaults.

"Russia must now end its military operations," she told a news conference.

Rice, who has no plans to visit Moscow on her visit to the region, repeated the U.S. accusation of "disproportionate force" by Russia and said Moscow knew that there would be consequences.

"I really do believe that the Russians understand that pushing the envelope here would have significant consequences for Russia's standing in the international system," she said.

She said it was not 1968 when then-Czechoslovakia was invaded and Russia felt it could threaten its neighbors, occupy a capital, overthrow a government and "get away with it."

"Things have changed," she said. (Reporting by Sue Pleming; Editing by Kristin Roberts)

AlertNet news is provided by