Associated Press
Separatist government forces of South Ossetia take positions on Thursday in Tskhinvali, the breakaway republic's capital.

TBILISI, Georgia — The capital of the separatist South Ossetia region came under heavy fire early today, just hours after Georgia's president declared a cease-fire following days of sporadic fighting.

South Ossetia's leader accused Georgia of treachery, but the Georgian government said its troops were responding to rebel attacks, news reports said.

The new violence after a week of clashes escalated fears that the confrontation could escalate into an all-out war that might engulf much of the Caucasus region and perhaps draw in Russia, which has close ties with the separatists.

"The assault is coming from all directions" around Tskhinvali, the South Ossetia capital, said a brief statement on the separatist government's Web site.

A statement from South Ossetian President Eduard Kokoity said his forces were in combat with Georgian troops on the outskirts of the city. "There is a bitter fight going on and significant damage is inflicted on the enemy," he said.

Georgia's government issued a statement saying the fighting started when separatists "began intensive firing on Georgian villages" near Tskhinvali, the Interfax and ITAR-Tass news agencies reported. The statement said the military "was forced to take adequate measures."

In a report from Tskhinvali, Interfax quoted Vladimir Ivanov, an official in a Russian peacekeeping force, as saying the fire included salvos by truck-launched Grad rockets.

Interfax quoted the president of North Ossetia, a Russian area bordering South Ossetia, as saying hundreds of volunteers were heading to join the fight "and we can't stop them." As many as 1,000 volunteers from Abkhazia, another Georgian breakaway region with close ties to Russia, planned to go to South Ossetia, Interfax quoted Abkhazian President Sergei Bagapsh as saying.

Hours before the new fighting, Georgian President Mikhail Saakashvili had announced a unilateral cease-fire in a television broadcast during which he urged South Ossetian leaders to enter talks on resolving the conflict.

He also proposed that Russia could become a guarantor of wide-ranging autonomy for South Ossetia, if the region remains under Georgian control.

South Ossetia agreed to hold fire until a meeting Friday between its deputy prime minister and Georgia's top envoy for separatist issues, Russian news agencies said, citing the head of the peacekeeping force in the region, Marat Kulakhmetov.

Heavy shelling overnight Wednesday in South Ossetia killed at least one person and wounded 22, officials said Thursday. It was some of the most severe fighting reported since Aug. 1, when six people were reported killed in firing around Tskhinvali.

Most of South Ossetia, which is roughly 1.5 times the size of Luxembourg, has been under the control of a separatist government since a war there ended in 1992. Georgian troops hold several parts of the region.