Biden, Putin speak on phone amid increased tensions over Ukraine, NATO

While speaking directly to one another via phone, President Joe Biden urged Moscow to use diplomacy to "de-escalate tensions with Ukraine," while Russian President Vladimir Putin warned that the U.S. would be making a mistake if sanctions are imposed on his country. 

Biden "made clear that the United States and its allies and partners will respond decisively if Russia further invades Ukraine," White House press secretary Jen Psaki said in a press release after a phone call Thursday afternoon between the two leaders.

Recent satellite images show that Russia has stationed even more troops on the border with Ukraine, according to reports. Despite statements from Moscow denying plans to invade, the Ukrainian Ministry of Defense states that about 120,000 Russian troops are deployed near the border. 

Biden, who conducted the call from his Wilmington, Delaware, home, encouraged Putin to begin diplomatic talks early next year through NATO's bilateral Strategic Stability Dialogue and at the Organization for Security and Cooperation in Europe. 

"President Biden reiterated that substantive progress in these dialogues can occur only in an environment of de-escalation rather than escalation," Psaki concluded.

Putin aide Yuri Ushakov told reporters that the Kremlin was satisfied with the call, which he said focused on security promises.

The United States has threatened sanctions if Russia invades its neighbor, which Ukrainian President Volodymyr Zelensky said earlier this month "won’t matter to anyone."

Putin threatened that U.S. sanctions would lead to a breakdown in relations between the two world powers, however. Putin told Biden "that it would be a mistake that our descendants would see as a huge error," Ushakov said, according to Reuters.

"Our president immediately responded (to the sanctions threat) that if the West decides in this or other circumstances to impose these unprecedented sanctions which have been mentioned then that could lead to a complete breakdown in ties between our countries and cause the most serious damage to relations between Russia and the West," Ushakov said.

In his Christmas and New Year greetings to Biden, Putin said, "I am confident that, following up on our agreements reached during the June summit in Geneva and subsequent meetings, we can move forward and establish an effective Russian-American dialogue based on mutual respect and consideration for each other’s national interests."