On Sunday, President Joe Biden will meet with Ukraine President Volodymyr Zilenskyy to voice support for Ukraine’s sovereignty. Russian military forces pile upA White House official stated Friday that the border was close to both countries.

The official stated that Biden will also review diplomatic plans to “help de-escalate” the crisis in the region. American and Russian officials will hold a meeting security talks on Jan. 10To discuss Russia-Ukraine tensions, and other topics.

This Thursday Biden in a 50-minute phone call urged Russian President Vladimir PutinTo reduce these tensions. Jen Psaki, White House Press Secretary, stated that he warned the U.S. would respond decisively to any Russian invasions of Ukraine.

Kremlin aide reportedly saidFollowing the discussion, Putin “explained in detail Russia’s fundamental principles in security proposals” and stated that Russia would seek to protect its security.

Since months Ukraine has been raising alarms regarding the buildup at Russia’s eastern border. Putin had previously claimed that Moscow was not planning to invade, despite its military presence. Pro-Russian separatists meanwhile have pushed into swaths of eastern Ukraine.

Putin also opposes Ukraine’s membership in NATO. This intercontinental military alliance of 30 nations is where any attack on one member can be considered as an attack against all. For years, Ukraine tried to join NATO.

In late November, Putin suggested Russia would retaliateIt would not be surprising if certain weapons systems were provided by the west to Ukraine. The threat of NATO expanding its military might to other Eastern European countries has been called by he.

Russia annexed Crimea Peninsula, Ukraine in 2014. Putin has claimed that Ukraine is essentially a part of Russia.

Biden had separate calls with Zelenskyy and Putin earlier in December. Biden and Zilenskyy met face-to-face at the White House in September.