U.S. President Joe Biden warned Russian President Vladimir Putin in a video call Tuesday that the United States and its allies would respond with strong measures if Russia invades Ukraine.

During their 2-hour secure virtual meeting, the White House said that President Biden “voiced the deep concerns” of the United States and its allies about Russia’s escalation of forces around Ukraine and “reiterated his support for Ukraine’s sovereignty and territorial integrity” while calling for de-escalation and a return to diplomacy. Biden also asserted that the United States and its allies would respond with “strong economic and other measures in the event of military escalation.”

National security adviser Jake Sullivan said during a press conference: “He told President Putin directly that if Russia further invades Ukraine, the United States and our European allies would respond with strong economic measures. There was a lot of give and take” between Biden and Putin, adding that Biden was “crystal clear about where the United States stands.” Sullivan added the administration was prepared to send supplies and other resources to Ukraine and other North Atlantic Treaty Organization allies if Russia further invades Ukraine.

Tuesday’s meeting came amid a U.S.-Russia relationship that’s been in decline for years. The White House said that Biden and Putin also discussed other issues, such as “the U.S.-Russia dialogue on Strategic Stability, a separate dialogue on ransomware, as well as joint work on regional issues such as Iran.”