Georgia's banking sites also suffered attacks that caused them to shut down their online systems, said David Tabatadze, a security officer with the Georgia Research and Educational Networking Association and Georgia's CERT. Some of those systems are still down, he said.

Tabatadze said that the majority of Georgia's Internet traffic is routed through Turkey, with some of it going through Russia. Although some news reports indicated Georgia's Internet traffic may have been shifted through Russia, Tabatadze said that's not the case.

"We have checked the traffic route on Ripe.net...and we did not see any traffic re-routing via Russia," Tabatadze said.

It appears that large groups of hackers are working together to take down the Web sites, but the attacks have been so intense that it will take a while to analyze, Tabatadze said.

Other CERTs around the world have been helping to provide information on the attacks, Tabatadze said.

The last few days have been a nerve-racking time for Georgians, said Tabatadze, who said he heard explosions on Sunday when Russian planes bombed air-traffic control stations near Tbilisi, Georgia's capital.

"You can't even imagine the situation," Tabatadze said. "This is a terrible end for Georgia."

On Tuesday morning, Russia announced it would stop military operations in South Ossetia and Abkhazia, saying the safety of its peacekeepers in the region had been secured.