Direct talks between Russian President Vladimir Putin and Ukraine's Volodymyr Zelensky would be "counterproductive", the Russian foreign minister said Monday, as delegations prepared for Turkey-hosted talks on Moscow's military operation.

Putin "has said he has never refused to meet President Zelensky. The only thing that he considers fundamentally important is for these meetings to be well prepared", Russian Foreign Minister Sergei Lavrov said in televised comments to journalists, after Zelensky called for a meeting with his Russian counterpart.

Lavrov said the current crisis has "been brewing so long, all these years, that a huge number of problems have built up, therefore just meeting and exchanging views on what you think and I think, that would just be counterproductive now".

Zelensky and Putin have met only once, at talks in Paris in 2019.

As the countries are set to resume in-person peace talks in Istanbul, Lavrov said Moscow maintains its demands for demilitarisation and "denazification" in Ukraine.

Putin has named these as Moscow's military goals, as well as for Ukraine to have neutral status. 

"Both the demilitarisation and the denazification of Ukraine are an essential component of the agreements that we are trying to achieve," Lavrov said.

"We have an interest in these talks ending with a result that will achieve the fundamental aims for us," the minister said.

He named the primary goal as "ending the killing in the Donbas region that has lasted eight years", referring to eastern Ukraine.

He added that Russia wanted Ukraine to "stop assimilating itself with the West, with NATO, in the military sense".

Ukraine must "stop being a country that is continually being militarised and where they try to deploy offensive weapons threatening Russia", he said.

The minister also called for an end to "efforts to encourage Nazi ideology and practices".

He said that Ukraine's armed forces are "permeated by officers from the so-called national volunteer battalions, which publicly preach Nazi ideas".

Lavrov also accused the West of "supporting the extermination of everything Russian in Ukraine", citing books and television broadcasts.