U.S. Secretary of Defense Lloyd Austin assured the three Baltic nations Saturday that they would not be on their own if faced with security threats from Russia, but he stopped short of promising a permanent deployment of American troops in the former Soviet republics.

Austin was in Lithuania as a massive Russian troop buildup and other actions have Western officials saying that Moscow could invade Ukraine at any time, although Russia has denied planning an invasion.

“They are uncoiling and are now poised to strike,” Austin said Saturday about the readiness of Russia’s troops to attack Ukraine.

Lithuanian officials voiced concern that Russian President Vladimir Putin’s alleged ambitions could expand to the entire region.

“The battle for Ukraine is a battle for Europe. If Putin is not stopped there, he will go further,” Lithuanian Foreign Minister Gabrielius Landsbergis said during a joint news conference with Austin.

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“They are choosing the way that is based on force. We need to send a very clear and unambiguous message that it would be faced by a very clear and swift response” Landsbergis said.

“I want everyone in Lithuania, Estonia and Latvia to know - and I want President Putin and the Kremlin to know - that the United States of America stands with our allies,” Austin said during the news conference in Vilnius, the Lithuanian capital.

Austin also met with Lithuanian President Gitanas Nauseda, Prime Minister Ingrida Simonyte and the defense ministers of Latvia and Estonia on his two-day visit to Lithuania.

Nauseda asked Washington for a permanent deployment of a rotating battalion in the Baltics, emphasizing that the situation in Eastern Europe continues to deteriorate.

“Russia’s military build-up on NATO’s eastern border changes the overall security situation. Therefore, the decision to reinforce security in the region with additional troops from the United States and to accelerate collaboration on military acquisitions is critical,” Nauseda said.

United States has deployed regular rotations of battle groups of about 500 soldiers and armored vehicles since 2019.

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Austin did not comment on the request to deploy permanent military units in Lithuania, Latvia, or Estonia.

“I do not have any announcements to make today. We will continue to assess situations and consult with our allies and make any necessary adjustments” Austin said.