The Russian and US delegations are due to begin talks focused on ending the war in Ukraine in Saudi Arabia at 7am GMT.

The Washington team is seeking to work towards a ceasefire in the Black Sea, allowing the free flow of shipping, and a broader cessation of fighting in Ukraine.

Mike Waltz, White House national security adviser, said the teams will discuss “the line of control” between the two countries, which he described as “verification measures, peacekeeping, freezing the lines where they are.”

He said other “confidence-building measures” are being discussed, including the return of Ukrainian children taken by Russia.

On Sunday, the US team also met with a Ukrainian delegation in the same building in Riyadh. Rustem Umerov, Ukraine’s defence minister, said that talks were “constructive and meaningful” and focused on the energy sector.

It comes as Ukraine’s state-owned railway Ukrzaliznytsia said on Monday that its online systems have been subjected to a large-scale targeted cyberattack, likely orchestrated by Russia.