President Obama denounced Russia's "brazen assault on the territorial integrity of Ukraine" and called for NATO partners to "stand united against Russia's aggression" in a speech to the people of Estonia on Wednesday.
Looking to reassure skittish Baltic allies who have watched Russian interference in Ukraine — another former Soviet republic — Obama declared that the U.S. would "defend the territorial integrity of every single" NATO ally.
"The defense of Tallinn and Riga and Vilnius is just as important as the defense of Berlin and Paris and London," Obama said.
Obama's visit to Estonia came ahead of a NATO summit in Wales, where world leaders are expected to meet to discuss ways to reshape the alliance to better face modern security challenges, including Russia's repeated incursions into Ukraine.
NATO countries are expected to announce the creation of a quick strike force that could rapidly react to a similar effort in allied countries that border with Russia, as well as more regular rotations of troops through Eastern Europe.
"This week, NATO must send an unmistakable message of support to Ukraine," Obama said, adding that forces "need the ability to deploy even faster in the times of crisis."
"The United States is working to bolster the security of our NATO allies and further increase America’s military presence in Europe."
The president also called on other European allies to match Estonia and the United States in devoting at least 2 percent of gross domestic product to defense spending.
But much of the president's speech was devoted to a harsh indictment of the Kremlin's actions, which he accused of violating international norms, including that "borders cannot be redrawn at the barrel of a gun."
Obama said the actions of Russian-backed separatists "evoke dark tactics from Europe’s past that ought to be consigned to history."
"Unrestrained nationalism in the last refuge of those who cannot or will not deliver real opportunity for their people at home," Obama said.
The president also argued that economic sanctions imposed by the U.S. and Europe were "hurting the Russian people."
"Russia is paying a price," Obama said. "Capital is fleeing, foreign investment is plummeting — because investors know today's Russia is a bad bet."
The president spoke shortly after Russian President Vladimir Putin said he was hopeful that separatists in eastern Ukraine could strike a peace deal with the central government in Kiev. Putin urged both sides to put down their arms, according to the BBC, and described the two sides as "very close" on a cease-fire agreement.
Earlier Tuesday, Ukrainian President Petro Poroshenko reported that the Kremlin had itself agreed to broker a cease-fire agreement. Kiev later retracted that statement, after Moscow dismissed the report and claimed no involvement in the clashes on Ukraine's border.