President Obama in a speech in Estonia on Wednesday sought to assure the Baltic nations that the U.S. military would come to their defense if Russia tries to extend its reach beyond eastern Ukraine.

“We will stand firm and united to meet the test of this moment,” Obama told Estonian students on the eve of a NATO summit in Wales.

“We will defend the territorial integrity of every single ally,” the president pledged. “An attack on one is an attack on all.”

Obama and western allies at the NATO summit this week will attempt to unite behind a blueprint to deter Russian President Vladimir Putin from stoking tensions in neighboring countries, following his repeated incursions in Ukraine.

The president touted the heightened American military presence in Europe and efforts to bolster the defense capabilities of NATO allies, saying that western nations were sending an unmistakable signal to Putin.

“Make no mistake: Russia is paying a price,” Obama said Wednesday. “Russia’s actions in Ukraine are weakening Russia.

"Justice will win because might does not make right," the president added.

Ukrainian President Petro Poroshenko on Wednesday announced a “lasting cease-fire” with Russia, but the Kremlin later denied such a development — and the Ukrainian president’s office retracted the original statement.

Still, Obama sought to allay Baltic fears over Russia’s actions.

“We’ll be here for Estonia,” Obama promised. “We’ll be here for Latvia. We’ll be here for Lithuania.”