US journalist Evan Gershkovich and ex-US Marine Paul Whelan have returned to the United States, hours after being freed from Russian detention in the biggest prisoner exchange between the two countries since the Cold War.
The White House negotiated the trade with Russia, Germany and three other countries.
The deal, negotiated in secrecy for more than a year, involved 24 prisoners - 16 moving from Russia to the West and eight sent back to Russia from the West.
They included Vadim Krasikov, convicted of murdering an exiled dissident in Berlin.
Biden and Vice President Kamala Harris, buoyed by the occasion, greeted freed Americans Gershkovich, Whelan and journalist Alsu Kurmasheva as they arrived at Joint Base Andrews in Maryland, late on Thursday.
Russian President Vladimir Putin met the prisoners returning to Russia in Moscow, saying they would be given state awards.
"Today is a powerful example of why it's vital to have friends in this world," Biden said earlier at the White House, flanked by relatives of freed prisoners.
Biden expressed gratitude to German Chancellor Olaf Scholz, who made the politically difficult choice to release Krasikov.
The deal provides the Biden administration with a marquee diplomatic success as the US presidential campaign, pitting Harris against Republican former president Donald Trump, enters its final months.
Still, the multi-country deal appears to be a one-off that does not reset the antagonistic US-Russia relationship, which hit new lows over Moscow's invasion of Ukraine.
Critics said freeing Russians convicted of serious crimes could encourage more hostage-taking by US foes.
"I remain concerned that continuing to trade innocent Americans for actual Russian criminals held in the US and elsewhere sends a dangerous message to Putin," Michael McCaul, the Republican chair of the US House foreign affairs committee, said.
Trump, who said he did not have details of the swap, asked whether "murderers, killers, or thugs" were released, posting on social media: "Just curious because we never make good deals, at anything, but especially hostage swaps."
Also involved in the deal were Poland, Slovenia, Norway and Belarus. Turkey co-ordinated the exchange.
The Kremlin said it pardoned and freed prisoners "with the aim of returning Russian citizens detained and imprisoned in foreign countries".
The last major US-Russia exchange, in 2010, involved 14 prisoners.
In December 2022, the countries swapped US basketball star Brittney Griner, sentenced to nine years for possessing cannabis oil, for arms dealer Viktor Bout, who was serving a 25-year sentence.
The release of Russians convicted in the West represented a victory for Putin, who had indicated he wanted Krasikov back.
Their homeland "had not forgotten you for a moment", he told them at the airport.
Krasikov is a colonel in the Russian FSB security service who was serving a life sentence for murdering an exiled Chechen-Georgian dissident in a Berlin park.
Among the Westerners freed, Gershkovich, a Wall Street Journal journalist, had been accused of collecting sensitive military information for the CIA, a charge he and the newspaper denied.
Whelan was serving a 16-year sentence in Russia on espionage charges he denied.
Rico Krieger, a German, had been sentenced to death in Belarus on terrorism charges.
He was pardoned by President Alexander Lukashenko, a close Putin ally, before being freed.
Also released was Kurmasheva, a Russian-American journalist jailed for more than six years on July 19, the same day as Gershkovich and Russian-British dissident and US resident Vladimir Kara-Murza, who was serving 25 years for treason after criticising Russia's invasion of Ukraine.
Released with them were human rights activist Oleg Orlov and Russian opposition politician Ilya Yashin.
Russian opposition figure Alexei Navalny, who died in an Arctic penal colony in February, was meant to have been part of the exchange, said Biden's national security adviser, Jake Sullivan.
The swap comes in the waning months of Biden's term after he ended his re-election bid in July.
Wall Street Journal editor-in-chief Emma Tucker posted an open letter on X, calling it a "joyous day".
