President Trump said Thursday that if unverified reports that the FBI had a mole inside his presidential campaign are confirmed, it would be a scandal to rival the greatest U.S. political scandal in the last century.

“Wow, word seems to be coming out that the Obama FBI ‘SPIED ON THE TRUMP CAMPAIGN WITH AN EMBEDDED INFORMANT,'” Trump tweeted. “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!”