“We are doing this for both the present and the future of our country. For many generations to come. Therefore, we have no alternative,” he added in a radio interview.
Russia launched its all-out offensive on Ukraine in February 2022, when its forces tried to capture the capital Kyiv and Putin publicly called for Zelenskyy to be toppled.
The conflict has since killed tens of thousands of people, devastated much of eastern and southern Ukraine and forced millions to flee their homes.
‘Mistaken’
Moscow’s army controls around one-fifth of Ukraine’s territory, including the Crimean peninsula annexed in 2014, and has been grinding forwards on the battlefield, with both armies suffering immense losses.
This week, Trump dismissed Russia’s military prowess and mocked its inability to quickly beat Ukraine.
In a post on Truth Social, he said Ukraine may “be able to take back their country in its original form and, who knows, maybe even go further than that”.
Russia rejected that notion.
“The idea that Ukraine can recapture something is, from our point of view, mistaken,” Peskov told reporters, including AFP.
Russia also bristled at the accusation it was weak.
“The phrase ‘paper tiger’ was used in relation to our economy,” Peskov said.
“Russia is more associated with a bear. And paper bears don’t exist. Russia is a real bear,” he added.
He did concede, however, that Russia’s economy – slowing after two years of rapid growth and with stubborn inflation – was “experiencing tensions and problems”.
Moscow’s finance ministry has proposed raising the sales tax from next year to help cover the costs of the offensive, which has pushed Russia into a budget deficit.
Kyiv and Washington want to cut off revenues from Moscow’s vital energy exports to further squeeze the Kremlin.
Ukraine has stepped up attacks on Russian energy sites in recent months, with its drones hitting a major Russian oil refinery in the central Bashkortostan region, triggering a large fire.
A Ukrainian drone attack also killed two people in the Russian port city of Novorossiysk, just east of the annexed Crimean peninsula, the local Russian governor said.
‘Zero’ results
Peskov also dismissed claims that Russia breached Nato’s airspace as “hysteria”, after Trump said the allies should shoot down Russian jets if they violate their territory.
Nato countries say multiple Russian fighter jets and drones have violated European member states’ airspace in recent weeks, accusing Moscow of testing the alliance’s boundaries.
With peace progress on Ukraine stalled, Peskov said a broader rapprochement between Moscow and Washington ushered in when Trump returned to the White House in January has yielded “close to zero” results.
Zelenskyy has hailed Trump’s apparent change of position as a “big shift”, though it is unclear if the US leader will follow through with concrete steps, such as more sanctions on Russia.
On the streets of Kyiv, there was scepticism.
“It’s just another opinion from Trump, which changes every hour,” 33-year-old Bogdan Tkachuk told AFP.
Svitlana Fetisova said she would want to see “more help, more action, not just words, because Ukraine is suffering”.
“I really want to believe that this is true and that finally the country responsible for the balance of peace in the whole world will turn to us,” she said.
– Agence France-Presse