The world’s most wanted terrorist, the Islamic State militant group's leader Abu Bakr al-Baghdadi, was killed Saturday in a U.S.-led raid in northwestern Syria, President Donald Trump announced Sunday.

Addressing the nation live from the White House, Trump said al-Baghdadi killed himself and three of his children, detonating a suicide vest as U.S. forces closed in after a "dangerous and daring" raid.

"Last night, the United States brought the world's No. 1 terrorist leader to justice," Trump said. "Abu Bakr al-Baghdadi is dead."

"Capturing or killing him has been the top national security priority of my administration," he said.

Trump and his top national security officials gathered in the White House situation room Saturday to watch what would be the most consequential military operation of his presidency so far. What they saw or later learned, as Trump told it, was just how a Hollywood script-doctor might have written it.

Eight helicopters were met with gunfire as they approached the compound, and returned fire to neutralize the threat. When the choppers landed "a large crew of brilliant fighters" emerged. They blew holes into the building to avoid a booby-trapped main door.

Trump said al-Baghdadi died "whimpering and crying and screaming all the way" into a dead-end tunnel.

"He reached the end of the tunnel as our dogs chased them down" and then detonated the suicide vest, killing himself and three of his children, Trump said.

"He was a sick and depraved man," the president added, "and now he's gone."

No personnel were lost in the operation, Trump said, but a large number of al-Baghdadi's "fighters and companions were killed with them." A U.S. military dog was injured during the operation, Trump later said.

Trump added that "test results gave certain, immediate and totally positive identification" that the group's leader was killed.

Trump thanked the nations of Russia, Turkey, Syria, Iraq and the Syrian Kurdish forces.

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Trump said the American forces landed with eight helicopters, flying over Russian-controlled airspace with their permission.

"We really had great cooperation," he said.

House Speaker Nancy Pelosi, D-Calif., who was not notified of the raid, said Americans saluted "the heroism, dedication and skill of our military and our intelligence professionals and acknowledge the work of our partners in the region."

"The death of al-Baghdadi is significant, but the death of this ISIS leader does not mean the death of ISIS," Pelosi said in a statement. "Scores of ISIS fighters remain under uncertain conditions in Syrian prisons, and countless others in the region and around the world remain intent on spreading their influence and committing acts of terror."

She added that the House must be briefed on the raid "which the Russians but not top Congressional Leadership were notified of in advance, and on the Administration’s overall strategy in the region."

Trump said earlier Sunday he did not give many congressional leaders advanced notice of the raid because he was afraid of "leaks."

"We were going to notify them last night, but we decided not to do that because Washington leaks like nothing I've ever seen before," he said.

Trump said he informed North Carolina Sen. Richard Burr and South Carolina Sen. Lindsey Graham, both Republicans, ahead of the raid. "Very few people" were made aware of the raid, he said, naming top officials in his administration and later Burr and Graham.

"I don't want to have men or women lost," he said. "I don't want to have people lost."

In his remarks, Trump named Americans who were killed at the hands of ISIS, listing Jim Foley, Steven Sotloff, Peter Kassig, and Kayla Mueller. Trump called their deaths "especially heinous."

Art and Shirley Sotloff, Steven Sotloff's parents, released a statement thanking all of those involved in the operation.

"While this victory will not bring our beloved Steven back to us, it is a significant step in the campaign against ISIS," they said. "It is our hope that our son's surviving captors, nicknamed 'the Beatles,' will be brought to justice, that all remaining hostages are returned to safety, and that the United States will take every measure to eliminate the resurgence of ISIS and terror in all forms."

Reports of al-Baghdadi's death had swirled on social media, with Trump himself appearing to hint at the news late Saturday.

Trump personally approved the operation, according to two people familiar with the matter.

A U.S. Special Ops mission targeted the ISIS leader near Barisha, Syria, overnight, sources told NBC News.

The mission included helicopters, jets and U.S. drones, the sources said.

The United States fired from the air and then landed and gathered intelligence, the sources said. Several other militants were also killed in a convoy. There were no U.S. casualties.

The news comes amid growing concerns around ISIS' potential resurgence and following the president's decision to pull troops from Syria's border in advance of a Turkish invasion.

The Kurdish-led Syrian Democratic Forces (SDF) — a key ally in the fight against the extremist group who accused Trump of abandoning them to the Turkish advance — claimed a role early Sunday in the operation in which al-Baghdadi was killed.

In his remarks, Trump said the Kurds gave the U.S. “information that turned out to be helpful."

Joshua Geltzer, a former top counterterrorism official on the National Security Council under Trump and President Barack Obama, told NBC News that al-Baghdadi's death would not undo the damage of the U.S. withdrawal.

“This is potentially a significant step in degrading ISIS' capacity to continue claiming preeminence in the jihadist movement, but it still doesn’t come close to overcoming the step backward the U.S. took in abandoning its ground partners against ISIS in Syria," he said.

Turkey also said that it had exchanged information and coordinated with the U.S. prior to the operation.

On Turkey's role, Trump said Sunday, "We dealt with them, they knew we were going in. We flew over some territory. They were terrific, no problem."

The death of al-Baghdadi brings an end to years of searching and speculation.

Detained by U.S. forces in Iraq in 2004, al-Baghdadi has led ISIS since 2010. He stood at the pulpit of the great medieval mosque in Mosul in 2014 to declare himself caliph, sovereign over all Muslims.

But with a $25 million U.S. bounty on his head, he had not been seen for five years.

Until April, when the group released an 18-minute video in which a bearded man resembling al-Baghdadi appeared sitting cross-legged on the ground with an assault-style weapon propped up against a wall and praised terrorists who carried out deadly Easter bombings of churches in Sri Lanka.

For years, reports also circulated questioning whether al-Baghdadi was alive.

Some reports had claimed that he had been killed in U.S. ordered-drone strikes, while others said he was hiding out in remote regions of Syria or Iraq.