The Russian president says he will only end the war in Ukraine if Kyiv agrees to drop its NATO membership ambitions and hand over four provinces Moscow claims as its own.
Kyiv rejected Vladimir's Putin's demands, set out on Friday, local time, as tantamount to surrender.
Mr Putin set out his demands for Ukraine's demilitarisation, unchanged from the day he sent in his troops on February 24, 2022, and said an end to Western sanctions must also be part of a peace deal.
He also repeated his call for Ukraine's "denazification", based on what Kyiv calls an slur against its leadership, given its democratically elected president is Jewish and lost relatives in the Holocaust.
Ukraine said the conditions were "absurd".
"He is offering for Ukraine to admit defeat," Ukrainian presidential adviser Mykhailo Podolyak said.
"He is offering for Ukraine to legally give up its territories to Russia.
"He is offering for Ukraine to sign away its geopolitical sovereignty."
Ukraine President Volodymyr Zelenskyy told Italy's SkyTG24 news channel that Mr Putin's comments amounted to an ultimatum, carefully timed to appear just before a Swiss peace summit for Ukraine.
"It is clear he (Putin) understands that there will be the peace summit," he said.
"It is clear he understands the majority in the world are on Ukraine's side, on the side of life.
"And on the eve of the summit, amid air raid sirens, the killing of people and missile attacks, he speaks as though he is issuing some sort of ultimatum."
US Defense Secretary Lloyd Austin told reporters at NATO headquarters in Brussels that Mr Putin was "not in any position to dictate to Ukraine what they must do to bring about peace".
Mr Putin has asked for the withdrawal of Ukrainian troops from the entire territory of the Donetsk, Luhansk, Kherson and Zaporizhzhia regions in eastern and southern Ukraine.
"The conditions are very simple," he said.
Russia claimed the four regions, which its forces control only partially, as part of its own territory in 2022, an act rejected by most countries at the United Nations as illegal.
Moscow annexed Ukraine's Crimean peninsula in 2014.
"As soon as they declare in Kyiv that they are ready for such a decision and begin a real withdrawal of troops from these regions, and also officially announce the abandonment of their plans to join NATO — on our side, immediately, literally at the same minute, an order will follow to cease fire and begin negotiations," Mr Putin said.
"I repeat, we will do this immediately. Naturally, we will simultaneously guarantee the unhindered and safe withdrawal of Ukrainian units and formations."
Russia controls nearly a fifth of Ukrainian territory in the third year of the war.
Ukraine says peace must be based on the full withdrawal of Russian forces and the restoration of its 1991 post-Soviet borders.
The weekend summit in Switzerland, which will be attended by representatives of more than 90 nations and organisations, is expected to shy away from territorial issues and focus instead on matters such as food security and nuclear safety in Ukraine.
The Kremlin has said the gathering will be "futile" without Russian representation.
Mr Putin's conditions appeared to reflect his growing confidence in Moscow's ability to impose its own terms as its forces have gradually advanced in recent months.
The Russian president added "the future existence of Ukraine" depended on it withdrawing its forces, adopting a neutral status, and beginning talks with Russia.
Kyiv's military situation, he said, would worsen if it rejected the offer.
"Today we are making another concrete, real peace proposal," Mr Putin added.
"If in Kyiv and in the Western capitals they refuse it as before, then, in the end, it is their business, their political and moral responsibility for the continuation of bloodshed."
Mr Putin was speaking in the same week that the US hit Russia with more sanctions, announced a 10-year security pact with Ukraine — seen as a potential precursor to eventual NATO membership — and reached a deal with its G7 allies to use interest on Russian assets frozen in the West to back a $50 billion loan to Kyiv.
Reuters