Trump says 'spies' in campaign would be unprecedented

US officials have told CNN there was no such source planted inside Trump's campaign to provide information to investigators. But Trump has raged over the story nonetheless.

"If they had spies in my campaign, that would be a disgrace to this country. That would be one of the biggest insults that anyone has ever seen. It would be very illegal aside from everything else," Trump said Tuesday in the Oval Office alongside his South Korean counterpart.

"It would make probably every political event ever look like small potatoes," he said. "So, we want to make sure that there weren't. I hope there weren't, frankly."

On Sunday, Trump demanded via tweet the Justice Department "look into whether or not the FBI/DOJ infiltrated or surveilled the Trump Campaign for political Purposes."

His tweets prompted the Justice Department to ask its inspector general to expand an ongoing probe into the surveillance of former Trump campaign aide Carter Page to include a review of whether the FBI was politically motivated in its investigation of Russian meddling in the 2016 US election.

"If anyone did infiltrate or surveil participants in a presidential campaign for inappropriate purposes, we need to know about it and take appropriate action," Deputy Attorney General Rod Rosenstein said in a statement.

The New York Times and The Washington Post have reported a confidential source spoke to Page and Trump campaign co-chairman Sam Clovis, as well as campaign adviser George Papadopoulos.

But officials have denied the confidential source was somehow embedded within Trump's campaign.

After a meeting with Trump at the White House on Monday, top officials at the Justice Department, the FBI and the Office of the Director of National Intelligence agreed to share highly classified information with lawmakers related to the use of the confidential intelligence source during the 2016 presidential campaign.

White House press secretary Sarah Sanders said Monday that chief of staff John Kelly planned to "immediately" schedule a meeting with the officials and leaders of Congress to "review highly classified and other information they have requested."

In the Oval Office on Tuesday, Trump said the meeting was "routine" and reiterated that Kelly was setting up a meeting with stakeholders.

"I think the Department of Justice wants to get down to it and I can tell you Congress does. So hopefully they will all be able to get together," he said.

But he refused to say whether he had confidence in Deputy Attorney General Rod Rosenstein, who oversees the Russia investigation, asking the reporter who posed the question to move on to her next question.

He characterized the alleged spying as a scandal of historic proportions.

"If they had spies in my campaign, during my campaign for political purposes, that would be unprecedented in the history of our country," he said.