By Christian Lowe

MOSCOW, July 9 (Reuters) - Bombings and gun battles in two breakaway regions of Georgia are threatening efforts to ease a standoff between Tbilisi and Moscow, hours before U.S. Secretary of State Condoleezza Rice visits the Georgian capital.

Rice, who arrives in Tbilisi on Wednesday, is expected to appeal for restraint on all sides but also express support for former Soviet Georgia's push to join the NATO military alliance, an ambition that has angered Russia.

"We said that both Georgia and Russia need to avoid provocative behaviour," Rice said as she flew to Europe on Tuesday. She also said "some of the things that Russia did over the last couple of months added to tensions in the region."

Georgia's pro-Western government has been locked in a tense confrontation with separatists in South Ossetia and Abkhazia and their Russian backers since early this year.

Unmanned Georgian spy planes shot down over one of the rebel regions had been the only casualties, but the conflict has recently turned bloody. Four people were killed when a bomb exploded in a cafe in Abkhazia on Sunday and two died when rebels clashed with Georgian troops in South Ossetia last week.

The rise in violence follows the resumption of talks between Moscow and Tbilisi and media reports that the two are trying to tease out a compromise deal likely to anger hardliners.

Russian President Dmitry Medvedev and Georgian President Mikheil Saakashvili have met twice in the past month. They made no breakthrough, but their talking at all was seen as progress.

Fyodr Lukyanov, a foreign policy analyst and editor of the journal Russia in Global Affairs, said the rise in violence could be linked to the talks.

"I think that in Tbilisi and Sukhumi and Tskhinvali, and possibly in Moscow, there are people who just do not want a solution to the conflict," Lukyanov said. Sukhumi is Abkhazia's capital and Tskhinvali is the main town in South Ossetia.

"And as far as possible they are taking steps so that these negotiations between the presidents should lead nowhere."

SEPARATIST CONFLICTS

The confrontation causes instability in a transit corridor for energy exports from the Caspian Sea. An oil pipeline built by a BP-led consortium runs through Georgia.

It is also an irritant in relations between Moscow and Washington, a staunch Georgian ally.

Sunday's cafe bomb was the deadliest single incident in Abkhazia for at least 18 months. Separatists in both regions accused Tbilisi of acts of aggression, but Georgia denied that and said the rebels were trying to fan tensions.

On Tuesday, Saakashvili said he would send in security forces unless South Ossetian separatists freed four Georgian soldiers they had detained. They were later released.

South Ossetia and Abkhazia threw off Tbilisi's control in separatist wars in the 1990s. Russia supports them financially and has peacekeeping troops in both regions. Georgia accuses Moscow of seeking to annex its territory.

"We should try to find ways to resolve the conflicts and get rid of the confrontation with Russia. There is such readiness from the Georgian side," Giga Bokeria, a Georgian deputy foreign minister, told Reuters.

Russia also says it wants a breakthrough, though a Kremlin spokesman said Medvedev on Saturday "drew Saakashvili's attention to the need to refrain from stoking tensions in the region and also stressed the need to continue talks with all parties involved".

The U.S. State Department said Rice would encourage all sides to "work in good faith", but many political analysts see the visit primarily underlining U.S. support for Georgia.

"It will be a signal to Russia that there is a limit to their actions," said Alexander Rondeli, president of think-tank the Georgian Foundation for Strategic and International Studies. (Additional reporting by Margarita Antidze in Tbilisi and Arshad Mohammed in Prague; Editing by Catherine Evans)

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