But President Dmitri A. Medvedev of Russia promised to “punish” those responsible for what he called “a deep violation of international law” by Georgia that he said had led to the deaths of Russian citizens and Russian peacekeepers stationed in Tskhinvali.

“I am obligated to defend the lives and dignity of Russian citizens, wherever they are located,” he said in an address carried on Russian state television. “We will not allow the unpunished killing of our fellow citizens. Those who are guilty will suffer the punishment they deserve.”