ASTANA Russian President Vladimir Putin said on Thursday he believed Republican presidential candidate Donald Trump was sincere about wanting to end the war in Ukraine, but that he did not know how Trump planned to do so if elected.

Putin, speaking at a news conference in Kazakhstan at the end of a regional security conference, commented after being asked about Trump's statements that he could end the Ukraine war swiftly if he won the White House race on Nov. 5.

"The fact that Mr Trump, as a presidential candidate, declares that he is ready and wants to stop the war in Ukraine, we take this completely seriously," Putin said.

"I am not, of course, familiar with possible proposals for how he plans to do this. This is the key question. But I have no doubt that he means it sincerely, and we support it (the idea of ending the war)."

The Washington Post reported in April that Trump had privately spoken about the option of allowing Putin to keep Crimea, which Moscow annexed from Ukraine in 2014, and the Donbas area - which Russian forces partially control - in return for peace, something Trump's campaign has not confirmed.

Two key advisers to Trump presented him with a plan to end the war that involves telling Ukraine it will only get more U.S. weapons if it enters peace talks, Reuters reported last month.

Putin said last month that Russia would end the war only if Kyiv agreed to drop its NATO ambitions and hand over the entirety of four provinces claimed by Moscow, demands Kyiv swiftly rejected as tantamount to surrender.

Putin said constructive dialogue between Moscow and Washington was impossible during a heated U.S. presidential election campaign and that Moscow would wait for the result and see what the new leadership does.

Asked what he made of the first televised debate between Trump and President Joe Biden, Putin said he had seen fragments.

Putin has said several times said that he feels Biden is preferable as the future U.S. president to Trump for Russia, even after Biden cast the Kremlin chief as a "crazy SOB" though some of his remarks have been ambiguous.

Asked on Thursday if his publicly stated preference for Biden had changed after the debate, Putin said: "Nothing has changed. Did we not know what could come? We knew."

"I saw some fragments," Putin said. "But I have enough to do."

Biden, 81, put in a stumbling performance during the debate, which brought questions about his age and mental fitness to the forefront of the campaign.

Putin said that he paid little attention to partial media reports about the debate though he could not ignore it as the United States remained a great power.

  - Reuters