U.S. President Barack Obama says the United States plans to bolster its military presence in Europe by sending in more troops and equipment.
At a joint news conference in Warsaw with Polish President Bronislaw Komorowski, Obama added that he was calling on the U.S. Congress to provide up to $1 billion to support the effort.
The move comes amid concern among NATO's Eastern European members in the wake of Russia's threatening moves in Ukraine.
Komorowski called the U.S. plans a "good answer" to Russia's actions.
Earlier on June 3, Obama said the U.S. commitment to the security of its allies in Central and Eastern Europe is "sacrosanct" and "a cornerstone of our own security."
The White House has said that the $1 billion European Reassurance Initiative, pending approval in the U.S. Congress, will rotate additional U.S. troops in the region and fund increased military exercises and training missions.
Few senators asked by RFE/RL on June 3 had knowledge of the proposal, beyond press reports. One Republican Senator, Lindsey Graham of South Carolina, said that he would oppose the measure.
"What about the Europeans securing Europe a little bit too?" he said. "We've got troops over there. How many NATO nations spend 2 percent of GDP on defense -- just a handful. Rather than me giving a billion dollars, which is not enough money to do anything, why don't we ask NATO nations to contribute more?"
Bob Corker (Republican-Tennessee), the ranking member on the Senate Foreign Relations Committee, released a statement that he was looking forward "to reviewing and understanding the details and objectives of the administration's proposal."
At his joint press conference with the Polish president, Obama also called on NATO members to increase their own defense spending to ensure the alliance's collective security.
He said the United States would "step up partnership" with countries such as Ukraine, Georgia, and Moldova.
Obama also called on Russia to use its influence with separatists in eastern Ukraine to make them lay down their weapons.
He said the United States wants good relations with Moscow and is "not interested in threatening Russia." But he also said Washington is prepared to increase sanctions if Russia continues its destabilizing actions in Ukraine.
He also said that rebuilding trust with Moscow will take "quite some time."
Obama called on Russian President Vladimir Putin to meet with Ukraine's President-elect Petro Poroshenko and recognize Ukraine's recent election as legitimate.
Obama is scheduled to meet for the first time with Poroshenko on June 4 in Warsaw.
Obama and Putin also could potentially meet later this week, when both plan to be in France for the 70th anniversary of the D-Day invasion that eventually led to the allied victory in World War II.
With reporting by Reuters, AP, and AFP