In this Thursday, June 8, 2017, file photo, former FBI director James Comey speaks during a Senate Intelligence Committee hearing on Capitol Hill, in Washington. (AP Photo/Andrew Harnik, File)

WASHINGTON — A highly anticipated report from the Justice Department’s inspector general criticizes former FBI director James Comey for his actions during the Hillary Clinton email investigation and includes new text messages from FBI personnel conveying political opposition to President Donald Trump.

Trump was set to receive a briefing Thursday on the 500-page report, which the president is widely expected to use to launch fresh attacks against not only Clinton but also the law enforcement officials behind special counsel Robert Mueller’s Russia probe, which Trump has repeatedly referred to as a “witch hunt.”

Perhaps the most damaging new revelation in the report, according to multiple people familiar with it, is a previously unreported text message in which Peter Strzok, a key investigator on both the Clinton email case and the investigation of Russia and the Trump campaign, assured an FBI lawyer in August 2016 that “we’ll stop” Trump from making it to the White House.

“[Trump’s] not ever going to become president, right? Right?!” the lawyer, Lisa Page, wrote to Strzok.

“No. No he won’t. We’ll stop it,” Strzok responded.

Though the inspector general condemned individual FBI officials, the report fell significantly short in supporting the assertion by the president and his allies that the investigation was rigged in favor of Clinton, according to a person familiar with its content, who spoke on the condition of anonymity to share findings before the report’s formal release.

A Justice Department spokesman confirmed Thursday that the report will include discussion of additional text messages between Strzok and Page. The inspector general has previously unearthed an exchange of pro-Clinton, anti-Trump texts between the two. Trump has seized on the exchange to argue bias against him within the FBI.

Deputy Attorney General Rod Rosenstein was expected to conduct the briefing for Trump, people familiar with the matter said. Lawmakers on Capitol Hill also will get briefings ahead of the report’s public release, aides said.

The Justice Department inspector general, Michael Horowitz, announced last week that his office would release its report Thursday – which is also Trump’s birthday.

The president “is really anxious to see the report,” said a person familiar with the planned Thursday briefing.

Before the release of the report, Senate Minority Leader Charles Schumer, D-N.Y., sought to counter any claims by Trump that it would show that bias against him by FBI officials has affected the Russia probe.

“Although we have not yet seen the inspector general’s report, there is no reason – no reason – to believe that it will provide any basis to call the special counsel’s work into question,” Schumer said in a speech on the Senate floor. “The IG report concerns an entirely separate investigation from the Russia probe that special counsel Mueller is conducting.”

Trump lashed out anew at the Russia investigation on Thursday in a pair of tweets.

“Now that I am back from Singapore, where we had a great result with respect to North Korea, the thought process must sadly go back to the Witch Hunt, always remembering that there was No Collusion and No Obstruction of the fabricated No Crime,” the president wrote.

In another tweet, he referred to the investigation as a “pile of garbage.”

The inspector general’s report was originally expected in May, and earlier this month, Trump questioned on Twitter whether its publication had been delayed because the findings were “being changed and made weaker.” The inspector general wrote in his letter to lawmakers announcing the June 14 date that his office was following the “ordinary processes” for completing reports.

John Lavinsky, a spokesman for the Office of the Inspector General, said in a statement this week that the office occasionally gives pre-release briefings to Congress and the media, adding that “for the Justice Department to brief the White House in the same manner and at the same time as the OIG briefs Congress and the press is consistent with this process.”

Lavinsky noted that Justice Department officials had similarly briefed the Obama White House in 2012 upon completion of its report on the scandal involving the gunrunning project known as Operation Fast and Furious. He added that “no changes are made to the OIG’s report on account of these briefings.”

In an interview with the Hill’s new television show “Rising,” which aired Thursday, Attorney General Jeff Sessions said he is open to firing employees if the inspector general’s report warrants it.

“I think it will be a lengthy report and a careful report,” Sessions said. “I think it will help us better fix any problems that we have and reassure the American people that some of the concerns that have been raised are not true.”

The Washington Post’s Matt Zapotosky and Josh Dawsey contributed to this report.