House Democrats decried President Trump’s real-time Twitter attack on former Ambassador to Ukraine Marie Yovanovitch during her testimony Friday, calling his remarks “witness intimidation” and threatening to pursue such a charge when they draft articles of impeachment against him.

As Yovanovitch sat before the House Intelligence Committee, describing a smear campaign against her led by the president’s personal attorney Rudolph W. Giuliani, Trump doubled down on a previous negative comment he’d made about her, punching out a message on Twitter alleging that “Everywhere Marie Yovanovitch went turned bad.”

“She started off in Somalia, how did that go?” the president wrote, referencing Yovanovitch’s posting in eastern Africa as deadly violence gripped the country early in her career with the State Department. “Then fast forward to Ukraine, where the new Ukrainian President spoke unfavorably about her in my second phone call with him.”

Trump was apparently referencing his July 25 call with President Volodymyr Zelensky and statements, critics have suggested, that Zelensky made only after he was prompted by Trump, who during the conversation referred to Yovanovitch as “bad news.”

“It is,” Trump then declared, “a U.S. President’s absolute right to appoint ambassadors. . . . They call it ‘serving at the pleasure of the President.’ ”

The reaction was swift and intense. Democrats labeled Trump’s comments both disrespectful and an attempt to stop the truth from coming out.

“It’s witness intimidation — and innocent people don’t intimidate witnesses,” said Rep. Eric Swalwell (D-Calif.), a committee member who was in the hearing room as Trump’s tweets were read to Yovanovitch. “Intimidating a witness and tampering with witness testimony is an obstructive act. And we have evidence that that’s happened here.”

“It’s a message to other potential witnesses what awaits them if they come forward,” said Rep. Peter Welch (D-Vt.), another member of the House Intelligence Committee. “Even for Trump, it’s pretty shocking. Blaming her for what happened in Somalia? Trashing a witness who was presenting the pride that she took in a life of service to the United States? It’s Trump outdoing himself.”

Later, at a White House event on health care, Trump defended his comments: “I have the right to speak. I have freedom of speech, just like other people do.”

But the president’s remarks, once more, put fellow Republicans in a tough spot as they strive to defend the president amid the House impeachment probe. GOP leaders Kevin McCarthy (R-Calif.) and Steve Scalise (R-La.) said they had not seen the president’s tweet.

“I haven’t followed the hearings today yet,” Scalise said, refusing to address questions about whether he felt it was appropriate for the president to tweet at Yovanovitch as she testified before Congress.

A few Republicans, including Rep. Lee Zeldin (N.Y.) and Chris Stewart (Utah), tried to show support for Trump. Stewart suggested that Yovanovitch has “been through much more than that” and “is not going to be intimidated by a tweet.”

Added Zeldin: “The president’s going to defend himself . . . I think it’s about the president wanting to ensure that the entire story is out there for the American public.”

Others were visibly uncomfortable. Rep. K. Michael Conaway (R-Tex.), who was in the room for the hearing, said of Trump’s tweet, “it’s not something I would do” but demurred about whether it amounted to witness intimidation, noting that he’s not a lawyer. Rep. Peter T. King (R-N.Y.), who has defended Trump in the past, called it “bad strategy on his part.”

Several Republicans in the hearing room Friday expressed their gratitude to Yovanovitch for her service to the country.

“You’re tough as nails and you’re smart as hell,” said Rep. Will Hurd (R-Tex.). “You’re an honor to your family. You’re an honor to the Foreign Service. You’re an honor to this country, and I thank you.”

Trump’s apparent dislike of Yovanovitch, whom he recalled from Kyiv in May, appears connected to the operation led by Giuliani to discredit her. The former New York mayor had accused her of harboring ill will toward Trump, though Giuliani’s Ukrainian sources for that information later recanted as Yovanovitch and the State Department fervently denied allegations that she was biased.

House Intelligence Committee Chairman Adam B. Schiff (D-Calif.) interrupted the regular line of questioning to denounce the president’s statements. He then asked Yovanovitch to react to Trump’s tweet, reading it before the TV cameras.

She called it “very intimidating.”

Federal law defines witness tampering as knowingly attempting to use intimidation, threats or corruptly persuading another person with the intent to influence, delay or prevent the testimony in an official proceeding. It is punishable by up to 20 years in prison, although under sentencing guidelines, people convicted of that crime typically receive far less time.

The president has attacked Yovanovitch before, most notably in his July phone call with Zelensky, during which Trump said to his counterpart that Yovanovitch was “going to go through some things.” Yovanovitch, who did not know about the statement at the time but found out later when a rough transcript of the conversation was released, said Friday that the president’s words “sounded like a threat.”

Throughout the special counsel investigation into Russia’s interference in the 2016 U.S. election, and the congressional investigation into his Ukraine dealings, the president has consistently attacked witnesses and investigators, often calling them corrupt or biased against him.

Democrats have picked up on the trend. House Speaker Nancy Pelosi (D-Calif.) told reporters Friday that while she hadn’t seen the tweet, it “seems to be a pattern” with the president. She declined to comment on whether it would be included in any articles of impeachment but jested when asked if Trump tweeting at Yovanovitch was appropriate: “Appropriate and president in the same sentence? Come on.”

Pelosi also stressed that “witness intimidation is a crime.”

Trump’s Friday tweets at Yovanovitch are unlikely to cross the legal threshold for witness tampering, experts said. James Trusty, a former Justice Department official who is now a partner at Ifrah Law, called them “dumb” and “certainly not a ‘perfect’ tweet, to use the president’s language.” But he said that “to try to immediately equate it to a federal obstruction or witness retaliation charge is almost as absurd. It just doesn’t rise to that level.”

“It’s absolutely fair to criticize the president for this, but that doesn’t make it criminal,” he said. “You’re allowed to criticize witnesses. You’re allowed to criticize the process.”

That doesn’t mean, however, that lawmakers won’t decide the tweets should not become part of their impeachment process, which is not bound by the rules of criminal courtrooms. “High crimes and misdemeanors” — the threshold for impeachment — is not defined in the Constitution, and thus can mean whatever lawmakers want it to.

Republicans outside of Congress were blunter than those in office who live in fear of Trump’s Twitter handle. Ken Starr, who led the investigation that led to the impeachment of former president Bill Clinton, said on Fox News that it was clear “the president was not advised by counsel in deciding to do this tweet.”

“Extraordinarily poor judgment,” he said. “Obviously this was quite injurious.”

Michael Steele, the former leader of the Republican National Committee, tweeted back at Trump his own dismay: “Dude! You realize she’s testifying LIVE?! Amb. Yovanovitch will respond to this tweet … yup, there it is. You just made her case of intimidation. Is no one in the room with you?”

Democrats suggested Trump’s visceral reaction to Yovanovitch’s testimony showed the effectiveness of her appearance. Yovanovitch used her opening statement to lay out her credentials as ambassador, talking about serving in war-torn Somalia and dodging bullets during a coup in Russia without body armor. She spoke of how her push to root out corruption in Ukraine made her the No. 1 enemy of corrupt people — individuals she said went to Trump allies to tell lies about her.

“I think the testimony is getting under his skin,” said Rep. Raja Krishnamoorthi (D-Ill.). “I think he can’t stand it.”