Barroso said Wednesday from Brussels the crisis in Ukraine serves as a reminder of the importance of democratic principles.
"It also reminds us how the outdated logic of the balance of powers is dangerous and wrong and we need to replace it with a logic of cooperation and dialogue, in full respect of international law," he said in a statement.
Russian President Vladimir Putin said this week he'd use military force only as a last resort to protect national interests in Ukraine.
Viktor Yanukovych, a Kremlin ally, was ousted last month as president of Ukraine following months of protest over a decision to suspend efforts to sign free trade and association agreements with the European Union. Yanukovuch accepted a promise of a $15 billion loan from Russia.
EU and U.S. officials said Russia is an important partner to Ukraine, but warned the Kremlin against overplaying its hand.
Russia's state-backed news agency RIA Novosti reported Wednesday lawmakers were weighing measures to freeze assets held by U.S. and European companies in the event sanctions are imposed on Russia for its actions in Ukraine's Crimea, home port of Russia's Black Sea fleet.