Austrian Chancellor Karl Nehammer said Mr Putin was operating in “his own war logic” and still believes the offensive in Ukraine is necessary despite mounting losses and tightening western sanctions on Moscow.
It came as Britain said Russia’s ultimate objective of bending Ukraine to the Kremlin’s will remained unchanged despite its shift of focus to the south and east.
Moscow on Sunday urged Ukraine to surrender the city of Mariupol, the scene of some of the war’s heaviest fighting and a strategically located port that would connect Russian-occupied territories in Donbas and Crimea.
Ukrainian President Volodymyr Zelenskyy said Russia was “deliberately trying to destroy everyone who is there” in Mariupol and warned that a massacre there could put a stop to any peace negotiations between the two sides.
“The more Borodyanka-like cases appear, there will be no chance that negotiations will be held,” he said, referring to one of the towns near Kyiv where grisly scenes were discovered after Russian forces withdrew.
Mr Nehammer told NBC’s Meet The Press he had confronted Mr Putin about the alleged war crimes by Russian forces during his closed-door meeting at the Kremlin last week.
“We have to look in his eyes and we have to confront him with what we see in Ukraine,” said Mr Nehammer, who was criticised in some quarters for becoming the first leader of an EU member state to visit Russia’s president since the country invaded Ukraine.
He said Mr Putin had responded that he would co-operate with an international investigation but did not trust the western countries accusing him of war crimes.
“I think he is now in his own war logic,” Mr Nehammer said. “He thinks the war is necessary for security guarantees for the Russian Federation.
“I think he believes he is winning the war.”
Ukraine says Russia has lost more than 20,000 troops and scores of tanks, helicopters and warplanes during the invasion. The Kremlin has been vague about casualties but has acknowledged significant losses.
Western countries have also reported low morale among the invading troops, while Russia suffered another setback last week when the flagship missile cruiser Moskva sank at sea.
But Ukraine is bracing for a new attack in the Donbas after Russia moved troops from Kyiv towards the south and east, amid suggestions Mr Putin wants a triumph to boast about by the time of the Victory Day parade in Moscow on May 9.
Britain’s Defence Ministry said in a regular intelligence update that Russia was moving military hardware from the territory of its ally Belarus towards eastern Ukraine, including locations close to Kharkiv and Severodonetsk.
Russian artillery continues to strike Ukrainian positions in the east “where Russia plans to renew its offensive activity”, the ministry said.
“Though Russia’s operational focus has shifted to eastern Ukraine, Russia’s ultimate objective remains the same,” it said.
“It is committed to compelling Ukraine to abandon its Euro-Atlantic orientation and asserting its own regional dominance.”
Mr Zelenskyy is demanding more weapons from western allies to fight off the Russian attack, especially in Donbas and Mariupol.
He said in an overnight address that allies should “give Ukraine all the necessary heavy weapons, planes, and, without exaggeration, immediately … so that we can reduce the pressure of the occupiers on Mariupol and unblock it”.
“The United States, the United Kingdom, Poland and several other countries support us very well today,” he said. “But they can do more, much more.”