Talks on a ceasefire in Russia's war with Ukraine will continue on Sunday in the Saudi Arabian city of Jeddah, US President Donald Trump's special envoy Steve Witkoff said Tuesday.

In an interview with Fox News hours after Trump held a lengthy phone call with Russian President Vladimir Putin, Witkoff said talks on a ceasefire deal "will begin on Sunday in Jeddah."

Referring to a ceasefire on energy infrastructure and targets in the Black Sea, Witkoff said: "I think both of those are now agreed to by the Russians. I am certainly hopeful that the Ukrainians will agree to it."