U.S. President Joe Biden and several leading NATO members have pledged support to Kyiv and the alliance's Central European members amid growing fears over Russia's troop buildup near its border with Ukraine.
Biden "reaffirmed the United States' unwavering commitment to Ukraine's sovereignty and territorial integrity," the White House said in a statement after he spoke with President Volodymyr Zelenskiy for about 90 minutes on December 9.
He also reiterated that the United States and its allies would impose economic sanctions on Russia and intensify defensive aid to Ukraine and NATO allies nearest to Russia in the event of an invasion by Russia into Ukraine, the White House said.
Biden also called the leaders of nine NATO members in Eastern Europe and discussed the Russian military buildup "and the need for a united, ready, and resolute NATO stance for the collective defense of allies."
Biden promised the so-called Bucharest Nine -- Romania, Poland, Hungary, Bulgaria, the Czech Republic, Slovakia, Estonia, Latvia, and Lithuania -- "additional military capabilities" and pledged to involve them in decisions about the region, Lithuanian presidential adviser Asta Skaisgiryte said.
But a White House statement did not mention specific military aid. It said Biden stressed a U.S. commitment to continued close consultation and coordination with transatlantic allies "as we work towards de-escalation of the current crisis through deterrence, defense, and dialogue."
Backing up Biden, French President Emmanuel Macron said he had spoken to Zelenskiy on December 10 and that the two leaders would talk again next week about initiatives to further peace talks on the conflict in eastern Ukraine, where Russian-supported separatists have been battling government forces since 2014.
"What we all want, Europeans and Americans, is to show that we are paying close attention to the situation," he told a joint news conference with Germany's new chancellor, Olaf Scholz.
Scholz noted Germany's concern over the situation at the Ukraine-Russia border,
"We will launch further activities to make sure that Ukraine has a good perspective," he said.
The diplomacy followed Biden's promise of meetings between envoys of Russia and major NATO allies to discuss Moscow's concerns about Ukraine joining the alliance and the possibility of "bringing down the temperature along the eastern front."
Biden said on December 8 that he hoped to announce a meeting of envoys soon to discuss "the future of Russia's concern relative to NATO writ large and whether or not we could work out any accommodations as it relates to bringing down the temperature along the eastern front [in Ukraine]."
The series of calls came two days after Biden held a videoconference with Russian President Vladimir Putin amid Western concerns about the presence of tens of thousands of Russian troops near Ukraine’s border.
Biden said he told Putin during their call that Moscow will face "severe economic sanctions" should Russian troops launch an attack.
Russia denies it is planning to attack, claiming Ukraine and NATO are provoking tensions. Moscow is demanding security guarantees against NATO’s expansion to Ukraine.
Tensions remained high on December 9, with Moscow accusing Ukraine of "provocation" over an incident involving one of its warships sailing near the Kerch Strait.
Russia's Federal Security Service said a Ukrainian vessel had headed toward the Kerch Strait that separates Russia and the Crimean Peninsula, which Russia illegally annexed in 2014, and failed to acknowledge a Russian request to change course.
Kyiv rejected the Russian complaints saying it was part of an "information attack" by Moscow.
The United States and NATO reject Putin's demands that they guarantee Ukraine won't be admitted to the Western military alliance.
White House spokeswoman Jen Psaki made it clear that Biden is hoping to resolve tensions through diplomacy and that does not include pressuring Ukraine to cede land to Russia as a means of deterring an invasion.
She called reports that administration officials suggested the United States will press Ukraine to formally cede some autonomy of its eastern territory to Moscow-backed separatists who are in the region "absolutely false."
Earlier, General Valery Gerasimov, chief of the Russian military's General Staff, warned Ukraine against trying to launch an offensive against the separatists in eastern Ukraine, saying any such action will be "suppressed."
Speaking to foreign military attaches, Gerasimov complained about what he called NATO's growing presence near Russia's borders and the increasing number of drills by alliance troops.
He also dismissed Western concerns about the Russian military buildup, arguing that Moscow is free to deploy its troops wherever it likes on its territory and calling the claim of a possible Russian invasion "a lie."
U.S. intelligence assesses that Russia has at least 70,000 troops near Ukraine and could be planning a multifront offensive as early as next year involving up to 175,000 troops.