But there has been significant posturing.
This week, Russia began military exercises with 150,000 troops along the border with Ukraine, sparking fears of a full-scale invasion. Russia has also given safe haven to Ukraine's deposed leader, Viktor Yanukovych, while armed gunmen took over Crimea's parliament building and raised the Russian flag. And on Friday, Ukrainian leaders said Russian naval troops blocked the airport in Sevastapol in Crimea, an autonomous Ukrainian region located on the northern part of a peninsula bordering the Black Sea.
In Kiev, Ukraine's new leaders on Thursday told Russia to back down.
"I am appealing to the military leadership of the Russian Black Sea fleet," said Olexander Turchinov, acting president since the removal of Viktor Yanukovich last week. "Any military movements, the more so if they are with weapons, beyond the boundaries of this territory (the base) will be seen by us as military aggression."
Soviets on the March
In the days of the Soviet Union, communist rhetoric made the case for military actions to stop rebellions in East Germany in 1953, Hungary in 1956 and Czechoslovakia in 1968.