President Obama in the central speech of a cross-Atlantic tour Wednesday lectured Russian President Vladimir Putin about the consequences of annexing Crimea, saying that western powers would not “look the other way” as the Kremlin attempts to flex its muscle in Eastern Europe.

Speaking to college students in Brussels, Obama accused Putin of spreading "propaganda" about U.S. and European intentions in Ukraine, saying the Russian leader's concept of geopolitics was outdated.

"Make no mistake, neither the United States nor Europe has any interest in controlling Ukraine," Obama said. "This is not another Cold War that we're entering into. After all, unlike the Soviet Union, Russia leads no bloc of nations, no global ideology. The United States and NATO do not seek any conflict with Russia."

The overarching goal of Obama's speech Wednesday was to trumpet the U.S. commitment to protecting European allies on edge over Russian troop movements in Ukraine.

Obama has dismissed Russia as merely a “regional power,” but some have questioned whether the White House is doing enough to counter a leader who is intent on expanding Russian prestige and influence — regardless of international law.

“We meet here at a moment of testing for Europe and the United States,” Obama told the audience.

“We must never take for granted the progress that has been won here in Europe and advanced around the world,” the president added. “That is what is at stake in Ukraine today.”

Since swiftly annexing Crimea, the Putin regime has shrugged off a series of sanctions imposed by the U.S. and western allies.

The Obama administration touted the suspension of Russia from the Group of Eight nations this week but did not impose additional sanctions against Russian officials for the takeover of Crimea.

Obama's address comes after a trying time for the U.S.-European relationship. The White House has been on the defensive over National Security Agency spying programs, a clash that has been overshadowed somewhat by the crisis in Ukraine.

“The borders of Europe cannot be redrawn with force,” Obama told the friendly crowd, saying the United States could not afford to “look the other way” as Russia makes its European power play.

“That kind of casual indifference,” Obama said, “would ignore the lessons that are written in the cemeteries of this continent.”