Witkoff was greeted by Kirill Dmitriev, Russia's investment envoy and head of its sovereign wealth fund. State media showed the two men strolling together through a park near the Kremlin, deep in conversation.
A source familiar with Witkoff's schedule told Reuters in Washington that Witkoff would meet with the Russian leadership on Wednesday. The Kremlin said he may meet President Vladimir Putin, but talks have not been confirmed.
Trump, increasingly frustrated with Putin over the lack of progress towards a peace deal in Ukraine, has threatened to impose heavy tariffs on countries that buy Russian exports.
He is exerting particular pressure on India, which along with China is a huge buyer of Russian oil. The Kremlin says threats to penalise countries that trade with Russia are illegal.
Putin is unlikely to bow to Trump's sanctions ultimatum because he believes he is winning the war and his military goals take precedence over his desire to improve relations with the US, three sources close to the Kremlin told Reuters.
"The visit of Witkoff is a last-ditch effort to find a face-saving solution for both sides. I don't think, however, that there will be anything of a compromise between the two," said Gerhard Mangott, an Austrian analyst and member of a group of Western academics who have met regularly with Putin over the years.
"Russia will insist it is prepared to have a ceasefire, but (only) under the conditions that it has formulated for the last two or three years already," he said.
"Trump will be under pressure to do what he has announced - to raise tariffs for all the countries buying oil and gas, and uranium probably as well, from Russia."
The Russian sources told Reuters that Putin is sceptical that yet more US sanctions will have much of an impact after successive waves of economic penalties during three-and-a-half years of war.
The Russian leader does not want to anger Trump, and he realises that he may be spurning a chance to improve relations with Washington and the West, but his war goals are more important to him, two of the sources said.
Witkoff, a real estate billionaire, has had several long meetings with Putin. He had no diplomatic experience before joining Trump's team in January, but has been simultaneously tasked with seeking ceasefires in the Ukraine and Gaza wars, as well as negotiating in the crisis over Iran's nuclear programme.
Critics have portrayed him as out of his depth when pitched into a head-to-head negotiation with Putin, Russia's leader for the past 25 years.
Critics have at times accused Witkoff of echoing the Kremlin's narrative. In an interview with journalist Tucker Carlson in March, for example, Witkoff said there was no reason why Russia would want to absorb Ukraine or bite off more of its territory, and it was "preposterous" to think that Putin would want to send his army marching across Europe.
Ukraine and many of its European allies say the opposite. Putin denies any designs on NATO territory, and Moscow has repeatedly cast such charges as evidence of European hostility and "Russophobia".
