U.S. President Joe Biden will speak Sunday with Ukrainian President Volodymyr Zelenskiy, a White house official said Friday, a day after Biden spoke with Russian leader Vladimir Putin on reducing tensions on the Ukraine-Russia border. 

Biden told reporters later Friday that he had again emphasized to Putin that a move on Ukraine would draw sanctions and an increased U.S. presence in Europe, where tensions are high amid Russia’s military buildup at the border. 

The U.S. and Russian leaders exchanged warnings over Ukraine in a 50-minute call on Thursday to address Russian military actions. 

“I made clear to President Putin that if he makes any more moves, if he goes into Ukraine, we will have severe sanctions. We will increase our presence in Europe, with our NATO allies, and there will be a heavy price to pay for it,” Biden told reporters as he left a Wilmington, Delaware, restaurant. 

Biden says Putin agreed on “three major conferences” next month with senior staff to help find a resolution and said he expected progress from those negotiations. However, he added, “I made it clear that it only could work if he de-escalated.” 

Asked if Moscow faces sanctions if it keeps troops on the border, Biden said, “I’m not going to negotiate here in public, but we made it clear that he cannot – emphasize cannot – move on Ukraine.” 

The Biden-Putin exchange set the stage for lower-level engagement between the countries that includes the U.S.-Russia security meeting on January 9-10, followed by a Russia-NATO session on January 12, and a broader conference including Russia, the U.S. and other European countries on January 13. 

U.S. Secretary of State Antony Blinken sought to lay the groundwork for those talks on Friday in calls with NATO Secretary-General Jens Stoltenberg and others, the State Department said. 

In conversations with the foreign ministers of Canada and Italy, Blinken discussed a united response to deter further Russian aggression against Ukraine.