'Large-scale Russian invasion' started war: Georgia

Georgia released a report Thursday claiming it faced a "large-scale Russian invasion" when its forces launched an assault on the rebel South Ossetia region last year, sparking a brief but bitter war.

The report, which claimed that Russia had been laying the groundwork for an invasion for months and that Georgia acted only in self-defence, was the first document to detail Georgia's long-standing allegations of how the war began.

It said a column of Russian tanks and armoured vehicles entered a tunnel leading to Georgia about 20 hours before Georgian forces were ordered to act.

The report comes on the eve of the first anniversary of the outbreak of the five-day conflict and amid continued tensions in the volatile region.

"On August 7, 2008, Russian armed forces ... launched a massive, coordinated, and -- given the scale of the enterprise -- premeditated assault on Georgia," the report said.

"The Georgian government concluded that it had been left with no choice but to order military action to counter what was rapidly becoming an invasion."

The report said that according to intelligence gathered by Georgia, about 150 tanks and armoured vehicles entered the Roki Tunnel leading to South Ossetia in the early hours of August 7.

Amid rebel artillery attacks on Georgian villages that night, the report said, more Russian army units were observed moving into the tunnel and Georgia "obtained solid evidence that a large-scale Russian invasion was in progress."

President Mikheil Saakashvili then ordered Georgian forces to start a "defensive operation" at 11:35 pm, the report said.

Among the documents attached to the report were previously classified telephone intercepts that Georgia claims show Russian forces were already on Georgian territory in the early hours of August 8.

In a key excerpt from 3:00 am that morning, a senior South Ossetian military official is allegedly heard saying in reference to Russian forces: "They have left the tunnel and they are coming. They are quite close to us."

Both sides have traded accusations of having started the war, with Russia insisting it moved into Georgia to defend South Ossetia from a Georgian attack aimed at retaking the rebel territory.

Russia moved deep into Georgia after its forces pushed the Georgian army from South Ossetia, occupying swathes of territory and bombing targets across the country.

Russia later mostly withdrew its forces to within South Ossetia and another breakaway province, Abkhazia, and recognised both regions as independent states.

The report also detailed what it said were "many months of sustained legal, political and military provocations against Georgia" by Russia before the war.

It said a campaign begun by Moscow in 2002 to give passports to residents of South Ossetia and Abkhazia was aimed at creating the pretext for Russian military action in Georgia.

Russia's December 2007 withdrawal from the Conventional Forces in Europe treaty was also partly in preparation for conflict with Georgia, the report said, and was followed by "an extensive military build-up" close to the Georgian border.

In the weeks before the conflict, the report said, Russia's sending of additional troops to Abkhazia and rebuilding of rail networks there were also part of pre-war preparations.

Lingering tensions from the war have soared in the run-up to the anniversary, with both sides trading accusations of small-scale attacks and "provocations" in recent days.

Russia said it has put its forces in South Ossetia on high alert and warned in a startling statement Saturday that it reserved the right to use force in case of Georgian "provocations." It has also accused Georgia of aggressively re-arming and charged the US with quietly supplying Tbilisi with arms.

The European Union's 225-strong monitoring mission in Georgia said Thursday it was intensifying its patrols because of "heightened tension" surrounding the anniversary.

"Our patrols are working day and night to monitor the situation on the ground, with the aim of maintaining security and stability," the mission said in a statement.