President Donald Trump is alleging that the Department of Justice put a "spy" inside his presidential campaign as part of an effort to frame him for crimes he says "didn’t commit."

"'Apparently the DOJ put a Spy in the Trump Campaign. This has never been done before and by any means necessary, they are out to frame Donald Trump for crimes he didn't commit,'" Trump tweeted Friday, quoting Fox Business Network anchor David Asman. "Really bad stuff!"

Moments later, Rudy Giuliani, one of Trump's lawyers, said on Friday that his legal team had been told "off the record" of an informant, but added that he didn't know if the information was correct.

"I don't know for sure, nor does the president, if there really was one," Giuliani told CNN. "For a long time we've been told by people that there was some kind of infiltration."

Trump's tweet Friday marked the second time in as many days that the president has claimed the government put a "spy" inside his campaign.

On Thursday — the anniversary of the appointment of special counsel Robert Mueller — Trump tweeted that former President Barack Obama had "spied on the Trump campaign," referencing a former Justice Department official who made the allegation on Fox News.

"Wow, word seems to be coming out that the Obama FBI 'SPIED ON THE TRUMP CAMPAIGN WITH AN EMBEDDED INFORMANT,'" Trump tweeted Thursday. "Andrew McCarthy says, 'There's probably no doubt that they had at least one confidential informant in the campaign.'

"If so, this is bigger than Watergate!" the president added.

Trump appeared to be citing an appearance Thursday morning on Fox News by McCarthy, a ex-federal prosecutor and former assistant U.S. Attorney, who has claimed there was an informant put into the Trump campaign.

"I've written a couple of columns in the last week or so pointing out that there's probably no doubt that they had at least one confidential informant in the campaign," McCarthy said on Fox News.

In an article in The National Review on May 12, McCarthy questioned whether the FBI had used a "human source" inside the Trump campaign in an attempt to confirm elements of the "Steele Dossier."