Without evidence, US President Donald Trump accuses Barack Obama administration of treason

U.S. President Donald Trump, trailing in opinion polls at a time of anti-racism protests and a surge in coronavirus cases, lashed out at the administration of Barack Obama, the country's first Black president, with a baseless accusation of treason.

The accusation, offered without evidence in an interview on Monday, was the Republican president's latest effort to tarnish Obama, a popular Democrat whom Trump has targeted for years, including falsely suggesting he was not U.S.-born.

Trump trails the presumptive Democratic nominee, Joe Biden, who was Obama's vice president, by 13 percentage points ahead of the Nov. 3 presidential election.

Under Trump, the U.S. Justice Department is reviewing a probe that found foreign interference in the 2016 election he won. He previously accused Obama of spying on his campaign but not treason.

Asked what crime might have been committed by spying, Trump told the Christian Broadcasting Network: "It's treason. Look, when I came out a long time ago, I said they've been spying on our campaign ... Let's see what happens to them now."

"(William) Barr is doing a great job as attorney general, let's see what they come up with," he said. Barr has said he does not expect Obama or Biden to be charged.

Representatives for Obama, who was scheduled to appear at a virtual fundraiser with Biden on Tuesday, said he had no comment on Trump's accusation.

U.S. intelligence agencies concluded that Russia interfered in the 2016 election to boost Trump's candidacy.

Former Special Counsel Robert Mueller's 21-month investigation documented a Russian campaign of propaganda and hacking to harm Trump's Democratic opponent Hillary Clinton. Mueller also documented numerous contacts between Trump campaign figures and Russians.