WASHINGTON — President Trump accused federal investigators of using a spy inside his campaign, repeating unconfirmed claims and saying it could be one of the “biggest political scandals in history!’’ The president also gave the scandal a name: “SPYGATE.’’

But hours later, Trump slightly backed off the accusations, telling reporters, “I hope it’s not true, but it looks like it is.’’

In a series of Twitter posts early Wednesday about the continuing Russia investigation, Trump briefly departed from his previous language about the possibility that the government deployed a spy inside his presidential campaign. Instead, he stated it as fact.

“Look how things have turned around on the Criminal Deep State,’’ Trump said in one post. “They go after Phony Collusion with Russia, a made up Scam, and end up getting caught in a major SPY scandal the likes of which this country may never have seen before! What goes around, comes around!’’

Trump has joined his allies in Congress in an offensive against the Justice Department, calling for the department to disclose the identity of an informant who approached several members of his campaign team who had been in contact with suspected Russian agents. The government’s use of the informant was to glean information about what the aides knew about the Russian efforts to hack into Democratic e-mails — not to spy on Trump’s campaign, according to people familiar with the matter.

Top intelligence and law enforcement officials are scheduled to meet with Republican lawmakers Thursday to share highly classified information about the informant.

Trump’s claims about the government spying on his campaign are part of a pattern for this president, who rails about injustice and political bias among the top officials at the Justice Department — officials he appointed. He has described the department as a “deep state’’ and Wednesday appeared to accuse it of criminal activity, calling it the “Criminal Deep State.’’

The latest accusation is similar to Trump’s claims in the early days of his presidency that former president Obama had Trump’s “wires tapped’’ in Trump Tower. His unsubstantiated claims were later proved to be false after a Justice Department review.

Until recently, Trump has couched the notion of an informant inside his campaign as a hypothetical. On Sunday, the president ordered the investigation into such claims, a move some say crossed a line intended to put constraints on executive power. The president and the White House do not make decisions about law enforcement investigations.

Former FBI director James Comey stood up for the bureau against Trump’s claims Wednesday, saying in a tweet, “Facts matter. The FBI’s use of Confidential Human Sources (the actual term) is tightly regulated and essential to protecting the country. Attacks on the FBI and lying about its work will do lasting damage to our country. How will Republicans explain this to their grandchildren?’’

Later in the day, Trump said it was Comey who lied. And the president said his efforts to learn more about the informant were not undercutting anything.

“We’re cleaning everything up,’’ Trump said, speaking to reporters before he boarded Marine One on his way to Joint Base Andrews. “What I’m doing is a service to this country.’’

He said he did the country a service when he fired Comey, as well. “If you look at the lies, the tremendous lies, if you look at all that’s going on, I think James Comey’s got a lot of problems,’’ Trump said.

Since his earliest days in office, Trump has lashed out against the government’s investigation into whether members of his campaign worked with the Russians in their efforts to interfere in the election.

Comey was fired, in part, by Trump because the president wanted to end the Russia investigation. The firing was the first in a series of events that culminated in the appointment of special counsel Robert Mueller.

Trump regularly pushes back against the Russia investigation, calling it a witch hunt, a scam, and phony.

Meanwhile, President Trump’s lawyer Rudy Giuliani switched gears Wednesday, saying that he would prefer the president grant an interview to Mueller’s office and that a decision would be made within ‘‘the next couple weeks.’’

‘‘I guess I’d rather do the interview. It gets it over with it, it makes my client happy,’’ he said.

‘‘The safe course you hear every lawyer say is don’t do the interview, and that’s easy to say in the abstract. That’s much harder when you have a client who is the president of the United States and wants to be interviewed.’’

Material from the Washington Post was used in this report.