The United States reaffirmed its commitment to Ukraine's sovereignty and territorial integrity Tuesday but stopped short of publicly backing Kyiv's call for a quicker path to membership in NATO.
"We've long been discussing that aspiration with Ukraine," White House press secretary Jen Psaki told reporters when asked about Ukraine's latest push to join the Western military alliance.
"We are strong supporters of them," she added. "But that is a decision for NATO to make."
Ukraine, along with the U.S. and other Western allies, has been expressing growing concern about Russian troop movements in recent days along the Ukrainian border that some see as an attempt to intimidate Kyiv.
In calls earlier Tuesday with both NATO Secretary General Jens Stoltenberg and Canadian Prime Minister Justin Trudeau, Ukrainian President Volodymyr Zelenskiy urged the alliance to send Moscow a message by allowing Ukraine to finally join.
"Reforms alone will not stop Russia," Zelenskiy tweeted following the call with Stoltenberg. "@NATO is the only way to end the war in #Donbas," he said, referring to the region in eastern Ukraine, parts of which are held by Russian-backed separatists.
"Ukraine's MAP (Membership Action Plan) will be a real signal for Russia," Zelenskiy added.
U.S. defense officials Tuesday declined comment on Ukraine's request for NATO membership, though they expressed continued concern about Russia's actions.
"We continue to see Russian forces arrayed along the border with Ukraine, in Crimea specifically, more toward the southeast," Pentagon press secretary John Kirby told reporters, calling the Russian movements concerning.
"We call on Russia to make their intentions more clear as to what they're doing with this array of forces along the border," Kirby said.
"We continue to call for the cease-fires that were called for by the Minsk Agreement … and to bring the temperature down," he said.
Ukraine says shelling by pro-Russian forces in Donbas has killed 24 soldiers this year and eight in just the past two weeks.
Russia has denied that its military movements pose a threat to Ukraine.
During a visit to India Tuesday, Russian Foreign Minister Sergey Lavrov described recent statements by Kyiv as worrisome and said Russia had reached out to other European countries.
Kremlin spokesman Dmitry Peskov also accused Kyiv of seeking to further destabilize the situation.
"So far we're not seeing an intention by the Ukrainian side to somehow calm down and move away from belligerent topics," Peskov said.
The separatists in Donbas have been fighting with Ukrainian forces since Russia seized the Crimean Peninsula from Ukraine in 2014.
The U.S. and other Western countries accuse Russia of arming the separatists and of sending Russian troops to aid their efforts.
Information from Reuters was used in this report.