US officials had expressed optimism Sunday that a Ukraine-Russia ceasefire deal could be reached in weeks after Washington proposed a halt in fighting in the three-year war after talks in Saudi Arabia, which Kyiv accepted. 

"I think we'll be talking about land... we'll be talking about power plants," Trump said aboard Air Force One.

"I think we have a lot of it already discussed very much by both sides, Ukraine and Russia. We're already talking about that, dividing up certain assets."

Washington and Kyiv's European allies are pressing Moscow to accept a halt in the fighting, but Putin has given no clear answer -- instead listing a string of conditions and raising "serious questions" over the proposal.

Trump's envoy for the conflict, Steve Witkoff, who met for several hours with Putin days ago, told CNN that he thinks "the two presidents are going to have a really good and positive discussion this week."

Trump, he added, "really expects there to be some sort of deal in the coming weeks, maybe, and I believe that's the case".

Ukraine's Volodymyr Zelensky on Saturday accused the Kremlin of not wanting to end the war. He warned that Moscow wanted to first "improve their situation on the battlefield" before agreeing to any ceasefire.

Earlier, Moscow said that US Secretary of State Marco Rubio had called his Russian counterpart Sergei Lavrov to discuss "concrete aspects of the implementation of understandings" at a US-Russia summit in Saudi Arabia last month. 

February's Riyadh gathering was the first high-level meeting between the United States and Russia since Moscow launched its invasion in February 2022.

"Sergei Lavrov and Marco Rubio agreed to remain in contact," the Russian foreign ministry said, with no mention of the US-suggested ceasefire.

State Department spokeswoman Tammy Bruce said Saturday that the pair had "discussed the next steps" on Ukraine, and "agreed to continue working towards restoring communication between the United States and Russia".

The Lavrov-Rubio call came hours after the UK hosted a virtual summit on Ukraine, at which Prime Minister Keir Starmer accused Putin of "dragging his feet" on the ceasefire.  

"The 'yes, but' from Russia is not good enough," Starmer said, calling for a stop to the "barbaric attacks on Ukraine once and for all".

On Sunday, Kyiv said Moscow had launched 90 Iranian-made Shahed drones onto nine Ukrainian regions.

In his reaction to the ceasefire earlier this week, Putin said the initiative would benefit primarily Ukraine, as Russian forces were "advancing" in many areas. He raised "serious questions" over the initiative. 

The proposal came as Russia -- which occupies swathes of southern and eastern Ukraine -- has the momentum in some areas of the front.

It has pushed out Ukrainian forces from parts of its Kursk region, where Kyiv hopes to hold onto Russian territory as a potential bargaining chip in any future negotiations. 

Putin said he wanted to discuss Moscow's concerns with Trump in a phone call. 

Late on Sunday, Zelensky said he had spoken with Canada's new Prime Minister, Mark Carney.

"The Prime Minister made the right points about how we need to step up pressure on Moscow," he said.

"The shadow fleet, the banking sector. We must impose all-out sanctions on everything that provides Russia with funding for its war. Only then can we force Putin to a just and lasting peace."

Carney is due in France on Monday for talks with French President Emmanuel Macron that will cover the war in Ukraine, before travelling to London to meet UK Prime Minister Keir Starmer.

Canada has the presidency of the G7 nations this year.

Also Sunday, Zelensky announced the chief of general staff of the armed forces, Anatoliy Bargylevych by Andriy Gnatov. Gnatov has been tasked with increasing efficiency in the armed forces.