The US Secretary of State, Marco Rubio has said that Ukraine will have to give up land seized by Russia for any agreement to end the war to be made.
Mr Rubio has flown to Saudi Arabia for crucial peace talks where Ukraine is expected to lay out its proposal for a sea and air truce.
President Zelensky’s chief of staff and defence and foreign ministers will meet the Trump team following last month's clash at the White House which saw the US pause military aid and intelligence sharing with Ukraine.
Boarding his flight, Mr Rubio said: “I’m not saying that alone is enough but it’s the kind of concession you would need to see in order to end the conflict."
He said it was important to “establish clearly Ukraine’s intentions” and to clarify that Ukraine “is prepared to do difficult things, like the Russians will".
He added: “Both sides need to come to an understanding that there’s no military solution to this situation.
"The Russians can’t conquer all of Ukraine and obviously it’ll be very difficult for Ukraine in any reasonable time period to sort of force the Russians back all the way to where they were in 2014.”
However, in a separate development, an overnight drone attack in Moscow was launched just hours before the crucial make-or-break talks, in which at least one person was killed.
The "massive" attack on the capital and its surrounding region damaged seven apartments and forced the suspension of one district train network.