WARSAW — During his presidential campaign, President Biden often reminded his audience about the heavy weight that the words of a president can carry.

“The words of a president matter,” he said more than once. “They can move markets. They can send our brave men and women to war. They can bring peace.”

They can also, as Biden discovered on Saturday, spark a global uproar in the middle of a war.

With nine ad-libbed words at the end of a 27-minute speech, Biden created an unwanted distraction to his otherwise forceful remarks by calling for Russian President Vladimir Putin to be pushed out of office.

“For God’s sake, this man cannot remain in power,” Biden said.

It was a remarkable statement that would reverse stated U.S. policy, directly countering claims from senior administration officials, including Secretary of State Antony Blinken, who have insisted regime change is not on the table. It went further than even U.S. presidents during the Cold War, and immediately reverberated around the world as world leaders, diplomats, and foreign policy experts sought to determine what Biden said, what it meant — and, if he didn’t mean it, why he said it.

Shortly after the speech, a White House official sought to clarify the comments.

“The president’s point was that Putin cannot be allowed to exercise power over his neighbors or the region. He was not discussing Putin’s power in Russia or regime change,” the official said.

Biden’s line was not planned and came as a surprise to U.S. officials, according to a person familiar with the speech who spoke on the condition of anonymity to discuss a sensitive situation. In the immediate aftermath of the remark, reporters rushed to find Biden aides and seek clarity on the president seemingly supporting a regime change in Russia.

But Biden aides demurred, refusing to comment as they scrambled to craft a response.

White House officials were adamant the remark was not a sign of a policy change, but they did concede it was just the latest example of Biden’s penchant for stumbling off message. And like many of his unintended comments, they came at the end of his speech as he ad-libbed and veered from the carefully crafted text on the teleprompter.

“The speech was quite remarkable,” said Aaron David Miller, a veteran diplomat and senior fellow at the Carnegie Endowment for International Peace. “This is one of those speeches where the one-liner in many ways drowns out the intent of the speech. Because that’s exactly what people are focusing on.”

Miller said that had the White House not immediately clarified, the comment would have led to a significant shift in policy and signaled to Putin that the United States would attempt to drive him out of office. It is unclear what the full impact of the comment may be in coming days.

“I’m risk averse by nature, especially with a guy who has nuclear weapons,” he said. “But will it have operational consequences? I don’t know.”

It likely signals to Putin what he already suspected about Biden’s true feelings, and it almost certainly will be used as part of Russia’s propaganda.

“I guess you can call this a gaffe from the heart,” Miller said. “If Biden could close his eyes tomorrow and have 10 wishes, one would be there’s a leadership change in Russia.”

But the comment also seemed to provide a window into Biden’s current thinking, and some of the mind-set that the administration has with regard to Putin.

“What it tells me, and worries me, is that the top team is not thinking about plausible war termination,” said Michael O’Hanlon, a senior fellow at the Brookings Institution and author of the book “The Art of War in an Age of Peace: U.S. Grand Strategy and Resolute Restraint.”

“If they were, Biden’s head wouldn’t be in a place where he’s saying, ‘Putin must go.’ The only way to get to war termination is to negotiate with this guy,” O’Hanlon said.

“When you say this guy must go you’ve essentially declared you’re not going to do business with him,” he added. “However appealing at an emotional level, it’s not going to happen. We can’t control it, and it probably won’t take place anytime soon.”

Over the past few weeks, Biden’s rhetoric on Putin — a man he once recounted telling to his face, “I don’t think you have a soul” — has become increasingly pointed. He has called him a “butcher” “pure thug” and a “murderous dictator.” So saying that he should be removed from power could viewed as the logical next step.

It also is in line with Biden at times articulating policy before his aides are ready. Last week, he called Putin a “war criminal,” which White House aides quickly said was simply him “speaking from the heart.” But within a few days, U.S. policy changed as Blinken also called Putin a war criminal and released a formal assessment on war crimes committed by Russia.

Biden’s comment was particularly striking because his administration has taken pains to avoid even implying that regime change is a goal of the Western response to Russia’s aggression.

Kremlin spokesman Dmitry Peskov told state news agencies, “That’s not for Biden to decide. The president of Russia is elected by Russians.”

Some officials, both in the U.S. and abroad, said Biden’s comment was an honest acknowledgment of reality — the U.S. will likely never have a normal relationship with Putin after the invasion. But the bigger worry may be that, in the short term, Biden’s rhetoric could escalate tensions and make any diplomatic off-ramp harder to find.

“There ought to be two priorities right now: ending the war on terms Ukraine can accept, and discouraging any escalation by Putin. And this comment was inconsistent with both of those goals,” said Richard Haas, a veteran diplomat and president of the Council on Foreign Relations.

“It discourages Putin from any compromise essentially — if you’ve got everything to lose, it frees him up. Why should he show any restraint?” Haas added. “And it confirms his worst fears, which is that this is what the United States seeks. His ouster and systemic change.”

He said the remark overshadowed an otherwise relatively smooth trip aimed at building additional support for Ukraine, bulking up additional sanctions enforcement and further unifying NATO allies.

“What’s frustrating about this is, up to now, the Biden administration has conducted itself with significant discipline. … This goes against the grain of their handling of this crisis,” Haas said.

“They obviously recognize that, they walked it back in a matter of minutes,” he added. “The problem is, from Putin’s point of view the president revealed his and our true intentions.”

David Rothkopf, a foreign-policy analyst and CEO of the Rothkopf Group, compared Biden’s speech to President John F. Kennedy’s speech in Berlin expressing solidarity with German citizens in 1963.

“There is within Biden’s comment a kernel of truth,” Rothkopf said. “Vladimir Putin can’t lay waste to a country, kill tens of thousands of civilians, commit serial war crimes and expect to be welcomed back into the community of nations. If Russia wants to be part of the community of nations, then they are going to have to produce change.”

“The statement I think is naturally going to be a bit of lightning rod as it has already been,” he added. “It shouldn’t distract from the much more important speech, but it also wasn’t wrong.”

Biden entered office with significant foreign policy experience and frequently touted his relationships with world leaders and ability to forge diplomatic compromise.

But if some other leaders operate as discrete poker players with cards close to their chest, Biden has often failed to hide his true intentions and thoughts when he is before a microphone.

The man who once confessed, “I am a gaffe machine,” has a long history of veering from the carefully crafted text of his speechwriters, and the inability to control his words has been a running joke among staffers for decades.

“I feel very capable of using my mouth in sync with my mind,” he told reporters, with more than a hint of defensiveness, in 1987.

At the launch of his 2008 campaign, Biden came under criticism for calling Barack Obama “the first mainstream African American who is articulate and bright and clean and a nice-looking guy.” Later, as Obama’s vice president, Biden was captured on a microphone whispering an expletive to Obama at the bill signing for the landmark health care law.

Biden drew significant ire from Obama and his aides when he announced his support for same-sex marriage before Obama or many other prominent politicians.

During the presidential campaign, Biden referred to Margaret Thatcher instead of the more recent British prime minister Theresa May, and he misstated when he had met with students impacted by a shooting in Parkland, Fla.

As president, aides have often worked to keep him on message. Sometimes that means limited exposure in formal settings — he waited longer than any president in at least a century to hold his first formal news conference — and it also means trying to keep him tightly to a script.

But there is little any aide can do when the president decides to extend his remarks and tuck in, almost as an aside, a declaration that he wants to see Putin removed from power.

“God bless you all. And may God defend our freedom,” he said after suggesting Putin’s removal. “And may God protect our troops. Thank you for your patience. Thank you. Thank you. Thank you.”

Viser reported from Washington.