Russian President Vladimir Putin has voiced hopes for further peace talks with Ukraine - but stressed his troops were "advancing on the entire front line", despite the threat of looming US sanctions if a ceasefire was not agreed upon.

"All disappointments arise from inflated expectations," Putin said, in an apparent reference to Trump's "disappointment" with the Russian leader for not bringing an end to the war.

Speaking a day after one of the deadliest Russian air attacks on Kyiv, he repeated his demands for Ukrainian neutrality and recognition of the occupied territories, which Ukraine views as a capitulation.

Ukrainian President Volodymyr Zelensky said he was ready to meet Putin "any time".

Speaking on Friday at the Valaam Monastery on an island in north-western Russia, Putin said he expected negotiations with Ukraine to continue, adding that he viewed "negotiations positively".