"We do not know what they were intended for, we are merely stating a fact," Dmitry Rogozin said.
The suspicious discovery, which could signal that Ukraine was involved in the recent conflict in Georgia's breakaway South Ossetia, was made in Senaki, in western Georgia.
Col.-Gen. Anatoly Nogovitsyn, deputy chef of Russia's General Staff, reported earlier in the day that Russian reconnaissance officers in Abkhazia had spotted a large number of cars with license plates of Ukrainian diplomats.
Commenting on the purpose of the plates, the Defense Ministry official said cars with such plates could have moved freely across Georgia and its breakaway republics of Abkhazia and South Ossetia.
"Diplomatic cars are not subject to checks on roads. They can carry any cargoes, including arms," Nogovitsyn said.