Ushakov said the summit would take place in a mutually convenient third country and that several more weeks were needed for preparations.
“This meeting has been planned for a long time,” Ushakov told reporters. “It has enormous importance for Russia and America, but it [also] has huge importance for the whole international situation. I think it will be the main international event of the summer.”
He said Moscow and Washington would announce the time and place of the summit on Thursday.
Ushakov was speaking after Putin held talks with US National Security Adviser John Bolton in the Kremlin, who is in Moscow in advance of an expected meeting between Putin and Trump in mid-July.
“Your visit here to Moscow inspires hope that we will be able to take first steps to restore full-fledged relations between Russia and the United States,” Putin told Bolton.
For his part, Bolton said that “direct contact between Trump and Putin is in the US national interest.”
“There are a wide range of issues, despite the differences between us, where both President Trump and President Putin think they may be able to find constructive solutions,” he said.
“I’d like to hear someone say that’s a bad idea.”
US allies who want to isolate Putin, such as Britain, or who are concerned about Trump’s attitude towards Russia are likely to be irritated by such a summit.
It is also likely to go down badly among foreign and domestic critics who question Trump’s commitment to NATO and fret over his desire to rebuild relations with Moscow even as Washington tightens sanctions.
The Trump administration has been long accused of colluding with Russia during the president’s 2016 election campaign.
However, in April, a probe by the US House of Representatives Intelligence Committee found no such evidence but described Trump’s associates as having several “ill-advised” Russian contacts.