In a highly anticipated video call on Tuesday, US President Joe Biden warned Russian President Vladimir Putin of “strong economic and other measures in the event of military escalation” in Ukraine, the White House said in a statement.

“President Biden voiced the deep concerns of the United States and our European Allies about Russia’s escalation of forces surrounding Ukraine and made clear that the US and our Allies would respond with strong economic and other measures in the event of military escalation,” the statement read.

“President Biden reiterated his support for Ukraine’s sovereignty and territorial integrity and called for de-escalation and a return to diplomacy,” the White House said.

Besides Ukraine, Biden and Putin also discussed the “US-Russia dialogue on Strategic Stability, a separate dialogue on ransomware, as well as joint work on regional issues such as Iran.”

The Kremlin had not yet released its readout of the call at the time of writing.

Just hours before the call got underway, Ukrainian officials charged Russia was continuing to escalate the crisis by sending tanks and snipers to war-torn eastern Ukraine to “provoke return fire.”

Ukraine’s Defense Ministry alleged that Russia is holding “training camps under the leadership of regular servicemen of the Russian Armed Forces.” The Kremlin hasn’t commented on the allegations

In a brief snippet from the start of the meeting broadcast by Russian state television, the two leaders offered friendly greetings to each other.

“I welcome you, Mr. President,” Putin said, speaking with a Russian flag behind him and a video monitor showing Biden in front of him.

“Good to see you again!” Biden replied with a chuckle. He then noted Putin’s absence from the recent Group of 20 summit in Rome. T

“Unfortunately, last time we didn’t get to see one another at G-20,” Biden said. “I hope next time we meet to do it in person.”

NATO talks

Ahead of the talks, Biden consulted by phone with European allies on Monday evening about Russia’s troop buildup on the Ukraine border, with a view to coordinate messaging and potential economic sanctions against Moscow.

He was to speak with them again on Tuesday following his call with Putin.

Biden is also expected to speak with Ukrainian President Volodymyr Zelenskyy in the coming days.

“We have a path forward that would impose significant and severe harm on the Russian economy” if Russia were to invade Ukraine, said White House Press Secretary Jen Psaki on Monday

Washington and Kyiv say Moscow has massed troops near Ukraine’s borders and accuse Russia of planning an invasion.