U.S. Vice President Mike Pence is in Estonia for talks on military support with the three Baltic members of NATO, to assume them the United States supports its allies who are concerned about Russian expansionism.

Estonia, Latvia, and Lithuania all have asked for tangible demonstrations of U.S. military support. Concerns about Russian expansionism have increased sharply in the Baltic region with Russia’s annexation of Crimes from Ukraine in 2014.

Pence was upbeat on his arrival in Tallinn, Estonia’s capital, on Sunday: “President (Donald) Trump sent me to Eastern Europe with a very simple message, and that is that America first doesn’t mean America alone.”

Pence will meet with all three Baltic presidents on Monday, then travel on to Georgia, where troops from the U.S. and other NATO partners began military ezxercises Sunday, and later to Montenegro, NATO’s newest member.

“Our message to the Baltic States, my message when we visit Georgia and Montenegro will be the same,” Pence said in Tallinn. “To our allies here in Eastern Europe: We are with you, we stand with you on behalf of freedom and it’s a great honor for me to be here.”

The NATO military exercise that began Sunday at Georgia’s Vaziani military base, Tbilisi, marks the first time that U.S. and German heavy military machinery was deployed in the former Soviet republic, which borders Russia.

Georgian President Giorgi Margvelashvili attended the opening ceremony at the exercise, dubbed Noble Partner 2017. A total of 2,800 soldiers from five NATO members – the U.S., Britain, Germany, Turkey and Slovenia – joined troops from NATO partner countries Ukraine, Armenia, and Georgia.

Pence said the U.S. is making it very clear “that Russia’s destabilizing activities, its support for rogue regimes, its activities in Ukraine are unacceptable.”

Referring to the prospect of increased U.S. sanctions against Russia, which Congress passed last week by an overwhelming margin, Pence said he and Trump “expect Russian behavior to change.”

“If Russia will change its behavior,” Pence said in Estonia, “our relationship can change for the good and can improve for the interests of both our countries, and for the interest of peace and stability in this region and around the world.”

Pence said he expects Trump to sign the sanctions bill, which also applies new penalties to North Korea and Iran as well as Russia, “very soon.”

The U.S. vice president is due to meet in Tallinn Monday with the three Baltic presidents – Kersti Kaljulaid of Estonia, Raimonds Vējonis of Latvia and Dalia Grybauskaitė of Lithuania. Trump’s deputy also will address Estonian and NATO troops who are part of the Western alliance’s Enhanced Forward Presence Program.