Russia on Saturday warned Georgia its military reserves the right to use force if the ex-Soviet state continues "provocations" in the Caucasus, one week ahead of the first anniversary of their 2008 war.
The Russian defence ministry accused Georgia of firing several times with mortars and grenades over the last four days on the capital of its rebel South Ossetia region which is recognised as independent by Russia.
"Such actions seriously worry the Russian defence ministry," the ministry said in a statement on its website.
"If such provocations posing a threat to the population of South Ossetia and the Russian military continue, the defence ministry reserves the right to use all the forces and means at its disposal."
The angry statement came just ahead of the August 7 anniversary of the start of the war, when a Georgian military attempt to retake South Ossetia was rebuffed by Russia. Moscow then sent troops and tanks deep into Georgian territory.
Georgian Interior Ministry spokesman Shota Utiashvili, speaking to AFP in Tbilisi, denied any shooting had taken place.
But the Russian defence ministry described the alleged Georgian actions as an "attempt by the Georgian leadership to inflame the situation in the region."
Ominously, it noted that the "events of August 2008 took place according to an analogous scenario."
Utiashvili described the statement as "very worrisome", saying Russia "may be searching for a pretext" for military action against Georgia.
"We hope the international community will condemn these clearly aggressive actions from the Russians," he said.
Georgia's deputy parliament speaker Mikhail Machavariani told Echo of Moscow radio: "Georgia has absolutely no plans to inflame the situation as we perfectly understand what might happen."
A spokesman for the European Union Monitoring Mission (EUMM) in Georgia, Steve Bird, said monitors had investigated the reports of violations early Saturday but found no evidence of shooting.
The EUMM -- the sole international presence in Georgia's conflict zones after the withdrawal of UN and OSCE observer missions -- has called on all sides to show restraint as the anniversary of the war approaches.
The Brussels-based International Crisis Group warned in a report last month that the withdrawal of OSCE and UN monitors was creating a "potentially explosive situation in which even a small incident could spark new fighting."
Russia and Georgia have repeatedly accused each other of ceasefire violations over the past months but this is the first time Moscow has issued a statement explicitly warning of the use of force.
After the war, Russian forces later mostly withdrew into South Ossetia and another breakaway Georgian region, Abkhazia, but Tbilisi is furious at the continued presence of thousands of Russian troops in both rebel regions.
As well as creating a rupture between Russia and pro-Western Georgia that shows no sign of healing, the war also sent relations between Moscow and Washington to their worst level since the Cold War.
US Vice President Joe Biden visited Georgia last week, backing its territorial integrity and the country's aspirations to join NATO, an idea that has particularly irked Russia.