Joe Biden told journalists at a glitzy bash that he is “working like hell” to free their colleagues who are being held overseas.
It came as celebs such as Julia Fox and John Legend gathered at the annual White House Correspondents’ Association dinner, often seen as a chance for politicians and comedians to trade barbs at each other.
Mr Biden, who announced recently he was standing again to be president, spoke to the parents of Evan Gershkovich at the event – the Wall Street Journal reporter who has been imprisoned in Russia on spying charges, which he denies.
Some of those in attendance wore “Free Evan” shirts.
Also in attendance was Debra Tice, whose son Austin went missing in 2012 after disappearing from a check point in Syria while working for the Washington Post and CBS.
The government has previously said it assumes Mr Tice is alive, and is working to bring him home.
“They are among hundreds of journalists around the world who are wrongfully detained for the simple act of doing journalism – which is not a crime,” said Tamara Keith, a White House correspondent for National Public Radio and the association’s president.
Brittney Griner was also invited to the event, after she was recently released from Russia detention over a drugs charge.
The basketball player was sent back to the US as part of a prisoner swap, and went to the White House dinner with her wife Cherelle, as guests of CBS News.
President Biden was given the chance to speak at the event, using it to target the US news media – mainly Fox News.
“Lies told for profit and power. Lies of conspiracy and malice repeated over and over again designed to generate a cycle
of anger and hate and even violence,” he said.
That cycle, Mr Biden added, has led some to ban books, and “the rule of law and our rights and freedoms to be stripped away.”
Zeroing in on what he described as “an extreme press,” Mr Biden at the same time joked that if he called Fox News “honest, fair and truthful then I can be sued for defamation”.
He was referring to the $787.5m settlement made between the network and Dominion Voting Systems.
Mr Biden also jibed about his predecessor, joking he had been offered $10 to keep his speech short.
“That’s a switch – a president being offered hush money,” Mr Biden added.
Other celebrities who attended included Oscar-winning actor Ke Huy Quan, former Olympian-turned politician Caitlin Jenner, and Harry Potter star Jason Isaacs.
Arnold Schwarzenegger opened proceedings with a pre-recorded video about freedom of speech, before the headliner Roy Wood Jr delivered his routine.
In particular, he took aim at Florida Governor Ron DeSantis, who is widely expected to announce a run for the presidency, touching on his ongoing feud with Disney, his book bans, and White House ambitions.