In an op-ed essay in the Financial Times, Medvedev justified Russia's invasion of its neighbor after Georgian President Mikheil Saakashvili moved to bring South Ossetia under Georgian control and Russian recognition Tuesday of South Ossetia and Abkhazia as independent countries.

"Only a madman could have taken such a gamble," Medvedev wrote. "Did he believe Russia would stand idly by as he launched an all-out assault on the sleeping city of Tskhinvali, murdering hundreds of peaceful civilians, most of them Russian citizens?"

Medvedev said that on the one hand Western leaders encouraged South Ossetians and Abkhazians by recognizing the independence of Kosovo from Serbia. At the same time, they "embraced" Saakashvili and encouraged him to pursue anti-Russian policies.

South Ossetia and Abkhazia, which both border Russia, have been autonomous for most of the time since Georgia became independent with the breakup of the Soviet Union.