Russian President Vladimir Putin said on Friday Moscow would only cease fire and begin peace talks if Ukraine gave up four of its regions and abandoned its NATO membership bid.

The Russian leader was outlining his "conditions" to halt the full-scale military offensive that he launched in February 2022, speaking on the eve of a major peace summit in Switzerland, orchestrated by Ukraine and its allies.

"Ukrainian troops must be completely withdrawn from the Donetsk People's Republic, the Lugansk People's Republic, Kherson and Zaporizhzhia regions," Putin said in a televised address to Russian diplomats in Moscow.

Russia claimed to have annexed the four regions in 2022, despite not having full control over any of them.

"As soon as Kyiv says it is ready to do this and begins really withdrawing troops and officially renounces plans to join NATO, we will immediately -- literally that very minute -- cease fire and begin talks," Putin said.

The Russian leader said he did not "rule out maintaining Ukrainian sovereignty" over the southern Kherson and Zaporizhzhia regions "on the condition that Russia has a strong land link with Crimea".

Military analysts have long said one of Russia's key goals in its offensive could have been to create a "land bridge" between Russia and the Crimean peninsula, along the southern coast of Ukraine.

But Putin and top Russian officials have typically tried to justify their offensive by saying they were protecting ethnic Russians and Russian speakers in the east of Ukraine from a "neo-Nazi" regime in Kyiv.

Ukraine and the West have rejected those allegations as baseless and cast Russia's military actions naked imperial-style aggression.

Russia unilaterally annexed the Crimean peninsula in 2014, triggering international outrage and armed conflict between Russian-backed separatists and Kyiv's forces in the east of the country.

Ukraine has said it will only countenance peace if Russia fully withdraws from its internationally recognised territory, including Crimea.