FBI Director Christopher Wray testifies during a House Homeland Security Committee hearing on Nov. 30. The FBI is under renewed scrutiny over the conduct of one of its senior agents on the separate probes into Russian intererence in the 2016 electoin and Hillary Clinton’s use of a private email server while secretary of state. (Reynold/Epa-Efe/Rex/Shutterstock)

FBI Director Christopher A. Wray sent a staff-wide message Monday in the wake of fresh criticism from President Trump, telling employees to keep focused on their mission and praising them for “example after example’’ of their professionalism.

The note did not mention the president’s criticism or his claim over the weekend that the FBI was “in Tatters.’’

Instead, Mr. Wray sought to reassure them of his faith in their work.

“We find ourselves under the microscope each and every day - and rightfully so,’’ Mr. Wray wrote. He noted that he has defended the agency to Congress, and expects to do so again later this week.

The note ends with one of Mr. Wray’s favorite phrases to his personnel: “Keep calm and tackle hard.’’

On Saturday, The Washington Post and the New York Times reported that Peter Strzok, a senior counterintelligence official who played a key role in investigating both the Hillary Clinton email case and possible connections between the Trump campaign and the Kremlin, had been removed from his job on the special counsel’s probe because of texts he exchanged with another senior FBI official.

In response, Trump tweeted over the weekend that the FBI’s reputation was “in Tatters — worst in history! But fear not, we will bring it back to greatness.’’

Strzok had been working as the top FBI official assigned to special counsel Robert S. Mueller III. When officials learned of his alleged indiscretions with another FBI official also involved in both the Clinton and Russia probes, he was immediately taken off the Mueller team and assigned to work in the human resources section of the FBI — widely understood by colleagues at the FBI to be a demotion.

Mueller is probing whether any Trump associates coordinated with Russian agents to try to interfere in the 2016 presidential race, and whether the president or other White House officials sought to obstruct justice in trying to end that investigation, according to people familiar with the matter. The president has long maintained he did nothing wrong, and he has called the probe a political witch hunt, saying it is Clinton, not him, who should be investigated. White House aides have repeatedly said Mueller’s probe will end soon, even though people close to the investigation have said it will last many more months, and possibly years.

Within the Justice Department and the FBI, officials have for months feared that revelations about Strzok’s alleged conduct with another FBI official could give fuel to calls from the White House and Republicans in Congress to end the Mueller’s probe.

The conduct by Strzok and the FBI official, a lawyer named Lisa Page, is now being investigated by the Justice Department’s inspector general. People familiar with the texts described the communications as disparaging of Trump and generally supportive of Clinton, although one of those individuals — a friend of Page — insisted the whole issue was “overblown.’’

Reacting to that news, Attorney General Jeff Sessions issued a statement saying the allegations, if true, “would raise serious questions of public trust.’’ He also said he had instructed Wray to “promptly make any necessary changes to his management and investigative teams consistent with the highest professional standards.”

One former law enforcement official joked darkly that he would be watching Sean Hannity’s broadcast on Fox News on Monday night to see if there would, in fact, be personnel moves made at the FBI or Justice Department — a reference to a moment in March when the White House decided to remove dozens of U.S. attorneys. The night before Trump made that move, Hannity — an informal adviser to the president — had used his program to urge the president to do that very thing.

Within the FBI, current and former officials said, there is still hope that the controversy will pass without firings or reassignments.

“It’s not so much demoralizing as it is just frustrating,’’ said Don Borelli, a former counterterrorism supervisor in the FBI.

“It was always a traditional FBI thing that when you’d get attacked in the news or something, there wouldn’t be a lot of stories or statements put out in self-defense. That’s just the way the FBI has done business,’’ he said.

In past decades, such criticism often came from lawmakers. What's different now, Borelli said, is that the salvos are coming from the president.

“Back then, it was always Congress. It was never tweets from the White House. This is a whole new thing,’’ he said. “I don’t think that anybody really feels like the FBI’s reputation is in tatters. They don’t like all this stuff, but it’s not going to change anybody’s attitude or the way they go about their business.’’

Thomas O’Connor, the president of the FBI Agents Association, issued a statement saying his group’s members act “with unwavering integrity and professionalism and a focus on complying with the law and the Constitution. . . . FBI agents are dedicated to their mission; suggesting otherwise is simply false.’’

At FBI headquarters, officials have demurred from addressing the president’s criticism directly.

The attorney general's comments appear to criticize the FBI more than defend the bureau. To some former federal law enforcement officials — particularly those who led the agency during the Obama administration — that is an alarming pattern.

For months, current and former Justice Department officials have voiced concerns about the president’s frequent criticism of federal law enforcement — that his comments hurt morale, raise doubts in the public’s mind about the Justice Department’s independence and integrity, and make it harder for senior officials to keep politics out of prosecutorial decisions.

On Monday, former attorney general Eric H. Holder Jr. called on current Justice Department leadership to “do your jobs, step up.’’

Noting that the top law enforcement officials have all been criticized or attacked in some way by the White House, Holder urged them to “support these people who keep our nation safe, insure justice and are last defense against a real threat to our democracy. . . . Leadership/Courage more important than job security.”