President Biden is slated to speak with Ukrainian President Volodymyr Zelensky on Thursday about the Russian forces gathering on the country's border.
The call with Zelensky will be followed by another during which Biden will brief the leaders of the Bucharest Nine (B9) about his two-hour phone call Tuesday with Russian President Vladimir Putin.
The B9 comprises the eastern flank of U.S.'s NATO allies, consisting of Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, and Slovakia.
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Biden's phone call with Putin reportedly grew tense at times as they spoke about the roughly 100,000 troops massing along the Russia-Ukraine border.
"There were no minced words. It was polite, but I made it very clear: If in fact, he invades Ukraine, there'll be severe consequences," Biden told reporters Wednesday morning about the call.
National Security Advisor Jake Sullivan announced the upcoming call between Biden and Zelensky on Tuesday.
"Our message to our friends in the Ukrainian government, as our message was today to President Putin, is that the United States supports the Minsk process, wants to see progress made towards a ceasefire, towards confidence-building measures. And that is the best way forward," Sullivan said.
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Biden on Wednesday dismissed the possibility of sending U.S. troops to Ukraine amid the Russian military buildup on the country's border.
"That is not on the table," Biden told reporters regarding whether the U.S. would send troops to Ukraine. "We have a moral obligation and a legal obligation to our NATO allies if they were to attack under Article 5, that's a sacred obligation. That obligation does not extend to ... Ukraine."
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Fox News' Michael Lee contributed to this report.