President Barack Obama told NATO member Baltic nations that the United States has their backs in the face of increasing Russian aggression in Ukraine, which isn’t a NATO member.

President Barack Obama speaks at Nordea Concert Hall in Tallinn, Estonia, Wednesday, Sept. 3, 2014. Obama is in Estonia for a one-day visit where he will meet with Baltic State leaders before heading to the NATO Summit in Wales. (AP Photo/Mindaugas Kulbis)

“We will defend our NATO allies, and that means every ally,” Obama said in remarks delivered at Nordea Concert Hall in Tallnin, Estonia, Wednesday. “In this alliance, there are no old members or new members, no junior partners or senior partners – there are just allies, pure and simple.”

A day before he heads to the United Kingdom for a NATO summit, Obama said the United States has increased its assistance in aircraft patrol to Baltic nations.

“I believe our alliance should extend these defensive measures for as long as necessary, because the defense of Tallinn and Riga and Vilnius is just as important as the defense of Berlin and Paris and London,” Obama said.

Obama later had a multilateral meeting with the leaders of Estonia, Lithuania and Latvia, then spoke with Estonian military officers.

“An attack on one is an attack on all. So if, in such a moment, you ever ask again, ‘who will come to help,’ you’ll know the answer – the NATO alliance, including the armed forces of the United States of America,” Obama said to applause in the concert hall. “We’ll be here for Estonia. We will be here for Latvia. We will be here for Lithuania.”

Obama has faced criticism at home for his response to Russia’s move against Ukraine, imposing sanctions that don’t seem to have yet had a deterrent effect on Russia, while ignoring calls to supply weapons for Ukrainians to defend themselves. Ukraine is not a NATO member, and thus lacks the same protection of guaranteed defense by allies.

“The United States will continue to help Ukraine reform to escape a legacy of corruption and build democratic institutions, to grow its economy, and, like other European nations, diversify its energy sources, because no country should ever be held hostage to another nation that wields energy like a weapon,” Obama said, referring to Russia. “We’ll continue to offer training and assistance to help the Ukrainian military grow stronger as they defend their country.”