US President Donald Trump and his White House challenger Joe Biden have fiercely clashed in the opening moments of their first live TV debate.
Mr Trump, a Republican, accused his rival of being beholden to socialists in his party, saying: “They’re going to dominate you, Joe, you know that.”
“I’m the Democratic party now,” retorted Mr Biden, a Democrat.
The 90-minute primetime duel in Cleveland, Ohio, is the first of three between the two rivals.
Opinion polls indicate Mr Biden has a steady single-digit lead over Mr Trump with 35 days until election day.
As the two candidates tussled over healthcare on Tuesday night, Mr Biden said: “Here’s the deal: everything he’s saying so far is simply a lie.
“I’m not here to call out his lies. Everybody knows a liar.”
Mr Trump hit back: “Joe, you’re the liar.”
Mr Trump challenged his rival to say whether he would pack the Supreme Court, adding more justices to tilt its ideological balance, as some Democrats have urged.
The president also demanded Mr Biden release a list of his nominees for the Supreme Court.
But Mr Biden would not be drawn.
“Will you shut up, man?” the Democrat said.
“Who’s on your list, Joe?” Mr Trump said. “He’s going to pack the court.”
The moderator, Chris Wallace, cut in to move the debate on.
“That was really a productive segment,” said Mr Biden with apparent sarcasm. “Keep yapping, man.”
Mr Trump replied: “The people understand, Joe. Forty-seven years, you’ve done nothing.”
The president later questioned why a company co-founded by his challenger’s son, Hunter Biden, had received $3.5m from a Moscow billionaire, according to a report released by Senate Republicans.
Mr Biden denied the claim, and the two shouted over one another.
As the moderator tried to cut in, the Democrat said: “It’s hard to get any word in with this clown, excuse me, this person.”
“Here’s the deal. We want to talk about families and ethics, I don’t want to do that, I mean, his family we could talk about all night.”