The United States and Russia agreed in Riyadh on Tuesday to press ahead with efforts to end the war in Ukraine, a U.S. official said, as Kyiv and its European allies watched anxiously from the sidelines and Moscow raised a major new demand.

U.S. State Department spokesperson Tammy Bruce said the two sides agreed to appoint "respective high-level teams to begin working on a path to ending the conflict in Ukraine as soon as possible in a way that is enduring, sustainable, and acceptable to all sides."

Russian negotiator Yuri Ushakov told reporters after more than four hours of talks: "It was a very serious conversation on all the questions we wanted to touch upon."