The Georgian and Polish presidents have accused Russian troops of firing near a motorcade carrying them close to the breakaway republic of South Ossetia.
Both South Ossetian troops and Russian forces in the area denied involvement. No-one was injured in the incident.
President Mikhail Saakashvili and his Polish counterpart Lech Kaczynski were planning to visit victims of fighting between Georgia and Russia in August.
The area has seen much cross-border gunfire since a ceasefire was agreed.

An independent report on the war between Russia and Georgia in August, is calling for an investigation into the conduct of all parties during the hostilities. The London-based human rights organization, Amnesty International, says it is concerned serious rights violations took place at the time.
Amnesty says all sides in the August conflict may have committed abuses. In its new report, Amnesty says Georgian and Russian forces and militia fighters in the breakaway South Ossetia region should be investigated for war crimes during the conflict.

Two former British military officers are expected to give crucial evidence against Georgia when an international inquiry is convened to establish who started the country’s bloody five-day war with Russia in August.
Ryan Grist, a former British Army captain, and Stephen Young, a former RAF wing commander, are said to have concluded that, before the Russian bombardment began, Georgian rockets and artillery were hitting civilian areas in the breakaway region of South Ossetia every 15 or 20 seconds.