Sergei Lavrov also said Georgia was preparing "terrorist acts" in the two republics.
"There is information that such provocations could be prepared and are being prepared, and not only regarding South Ossetia and Abkhazia," he said.
The deployment of the observers would, Lavrov said, "prevent any such attempts [at terrorist attacks]," and also "thoughts about" provocations in the conflict zone.
Lavrov also said that despite the large-scale destruction in Tskhinvali, the South Ossetian capital, Moscow would find a way to accommodate the Russian ambassador to the republic and his staff there.
Russia recognized South Ossetia and Abkhazia on August 26. Georgian forces attacked breakaway South Ossetia on August 8, triggering a Russian operation to "force Georgia to peace." Most residents of South Ossetia and another breakaway region, Abkhazia, have Russian citizenship.
Western nations strongly criticized Russia for its "disproportionate" response to Georgia's attack, and its recognition of South Ossetia and Abkhazia. So far only Nicaragua has followed suit, but Belarus looks likely to do so later this month.
Abkhazia and South Ossetia broke away from Georgia following the collapse of the Soviet Union in the early 1990s amid bloody conflicts which claimed thousands of lives.
