CBS News, the BBC's US media partner, reported that Hubbard had been in poor health and was expected to be flown to Texas for treatment. Witkoff gave praise to Putin for releasing Hubbard, saying: " You talk so much about my president, President Trump, being a humanitarian - you are a humanitarian also sir, and I salute that.

I commend you." Hubbard was later seen thanking Witkoff as they met separately.

Putin's financial adviser Kirill Dmitriev was also present. Writing on social media after Russian state media reported the release, Trump said it had followed a request he "made directly" to Putin last week.

In the past, detained Americans have primarily been released from Russia through prisoner swaps. The US state department had previously classified Hubbard, from Michigan, as "wrongfully detained" and Trump on Tuesday had suggested that his release may be imminent."

Russian prosecutors had accused Hubbard of joining a Ukrainian military unit and receiving training and weapons. But his sister, Patricia Fox Hubbard, previously told Reuters that this was unlikely because of his older age and his disinterest in the military.

Hubbard's son, Joseph Coleman, who is an Orthodox priest, said in a statement that he had prayed for many years for his father's release. " As I await the blessing of embracing him again, I receive his freedom not as a political victory, but as a gift of mercy," Coleman said.

A lawyer for Hubbard, Martin De Luca, posted on social media on Wednesday: " The road to peace is difficult, but its human dividends need not wait for a final agreement." A spokesman for Putin, Dmitry Peskov, told Russian media that American officials had been asking Russia to release Hubbard for some time, and Putin decided to do so for humanitarian reasons.

Witkoff, who had attended talks with Ukrainian President Volodymyr Zelensky in Oslo the previous day, also asked Putin to consider a number of proposals agreed in the Norwegian capital, including renewing trilateral peace talks with Ukraine to try to end the war. Putin has not publicly commented on whether any of the proposals would be acceptable for Moscow.

The Russian leader has so far rejected all proposals from Ukraine and its European allies to freeze the vast front line as it is and start peace talks. He thanked Putin for the deal struck with Washington earlier this month to import Russian diesel, saying Trump was "deeply grateful" for it.