Ukrainian President Volodymyr Zelensky on Saturday said Russian leader Vladimir Putin is "lying" about the implementation of a ceasefire in Ukraine and about the situation at the front.
"Putin is lying to everyone about the situation on the ground, especially about what's happening in the Kursk region, where our Ukrainian forces continue their operations," Zelensky said, adding "Putin is also lying about how a ceasefire is supposedly too complicated."
Russia earlier this week did not immediately agree to a 30-day ceasefire proposed by the United States, as President Vladimir Putin raised questions about the initiative.
"They want a stronger position before the ceasefire," Zelensky said at a press conference in Kyiv.
"I think the delaying of the process is exactly because of what I said. They want to improve their situation on the battlefield," he added.
The ceasefire proposal comes as Russia has the momentum in many areas of the front in Ukraine, three years into its invasion.
Moscow has also ousted Ukrainian troops from swathes of Russia's Kursk region, where Ukraine had led a shock offensive last summer.
Zelensky said that by not agreeing to the ceasefire, Putin was also going against Trump -- who has made some friendly statements on Russia -- and accused Moscow of trying to find ways not to end the war.
"Today Putin is the one who doesn't agree with what Trump has proposed," he said.
He said a 30-days ceasefire would allow negotiations on a long-term peace, though he ruled out ceding any territory to Russia.
"The United States raised this issue at a meeting in Jeddah. They got the Ukrainian position," Zelensky said, referring to talks between US and Ukrainian teams in Saudi Arabia.
"Our position is that we do not recognise the occupied Ukrainian territories as Russian in any case," he repeated.
Zelensky said the issue of territories was complex and should be "resolved later, at the negotiating table".
Russia has occupied large parts of southern and eastern Ukraine, with Moscow claiming to have annexed four Ukrainian regions, despite not controlling them fully.