Roman Abramovich has been pushed out of peace talks between Russian and Ukraine, the Kremlin has confirmed.
The Chelsea football club owner was involved in the early stages of efforts to broker a ceasefire.
Shortly after Russian President Vladimir Putin ordered his troops into Ukraine, Mr Abramovich’s spokesman said the billionaire was “trying to help” bring an end to the violence.
Ukrainian President Volodymyr Zelenskyy is said to have believed the tycoon could serve as a useful intermediary between Kyiv and Mr Putin’s inner circle, and put pressure on the Biden administration to refrain from imposing sanctions on him.
However, it was not known how influential Mr Abramovich, 55, would be in any negotiations. His mother, Irina, was born in Ukraine and he has close ties to Mr Putin.
The Russian billionaire was approached by Kyiv officials with a request to act as a go-between, his representative said.
On the fifth day of the war, he travelled to Belarus in an “advocacy role” and was praised by a senior Ukrainian politician for his “very positive” intervention.
Dmitry Peskov, the Kremlin’s spokesman, confirmed Mr Abramovich’s role in the early stages of peace talks but said he had been sidelined.
“He did take part at the initial stage,” Mr Peskov said. “[But] now the negotiations are between the two teams, the Russians and Ukrainians.”
More than a month into the conflict, efforts are still continuing to reach a peace settlement as the death toll mounts and western nations ratchet up sanctions against Russia.
Dmitry Medvedev, former president of Russia and deputy head of the Security Council, said it is “foolish” to believe sanctions against businesses in the country could have any effect on the Kremlin.
The sanctions will only bring together Russians and not result in popular discontent with the authorities, Mr Medvedev told Russia's RIA news agency in an interview on Friday.
The West has imposed an array of sanctions on Russia after its invasion of Ukraine, but the Kremlin says it will continue the assault until it accomplishes its goals of Ukraine's “demilitarisation and denazification".
Some of the sanctions have been aimed at billionaire businessmen believed to be close to Mr Putin.
“Let us ask ourselves: can any of these major businessmen have even the tiniest quantum of influence of the position of the country's leadership?” Mr Medvedev said. “I openly tell you: no, no way.”
He claimed opinion polls showed three quarters of Russians supported the Kremlin's decision to send troops into Ukraine and even more supported Mr Putin.
He lashed out at Russians who spoke against the invasion while staying outside Russia.
“You can be dissatisfied with some of the authorities' decisions, criticise the authorities — this is normal,” he said. “But you cannot take a stand against the state in such a difficult situation, because this is treason.”
Thousands of people were detained earlier this month across Russia during protests against Moscow’s invasion of Ukraine, according to an independent protest monitoring group.