The French news portal "Intelligence online" had previously reported on such plans.
According to the report, Russia's ambassador to the Holy See, Ivan Soltanovsky, had invited the Pope to Moscow.
Francis had agreed to a visit next June.
"This is not true," Vatican spokesman Matteo Bruni commented on the report when asked by journalists on Wednesday.
The Pope had already been invited to Ukraine several times since the start of the war.
Francis showed his willingness in principle, but only in connection with a visit to Moscow.
An invitation from the Kremlin has not yet been officially issued.
Pope Francis has been calling for an end to the fighting since Russia's invasion of Ukraine.
He recently made headlines with his statements on a negotiated peace in Ukraine.
His peace envoy, Cardinal Matteo Zuppi, held talks in Moscow, Kiev, Washington and Beijing last year.