Joe Biden reaffirms US support for Ukraine's sovereignty in first phone call with Russia's Putin

US President Joe Biden spoke on Tuesday with Russian President Vladimir Putin for the first time over the phone since his inauguration.

A statement issued by the White House confirmed that Biden reaffirmed the support of the US for the sovereignty of Ukraine in the face of Moscow’s support for separatists in the east of the country and its continued occupation of Crimea.

The two leaders also discussed willingness to extend New START for five years, agreeing to have their teams work urgently to complete the extension by February 5. 

Signed in 2010, the New START (Strategic Arms Reduction Treaty) is a cornerstone of global arms control.

It limits the number of strategic nuclear warheads deployed by the United States and Russia to 1,550 each as well as the number of land- and submarine-based missiles and bombers that deliver them.

The statement read that President Biden made clear that the US will "act firmly" in defense of its national interests in response to actions by Russia that harm US or its allies.