President Donald Trump on Sunday, Oct. 27, announced that Abu Bakr al-Baghdadi, the elusive Islamic State commander, died during a U.S. military operation in Syria, an important breakthrough more than five years after the militant chief launched a self-proclaimed caliphate that inspired violence worldwide.

"Last night the United States brought the world's No. 1 terrorist leader to justice," Trump said in a televised announcement from the White House. "He was a sick and depraved man, and now he's gone."

In what the president called a "dangerous and daring" nighttime operation, helicopters inserted a team of American Special Operations troops into a volatile area of northwest Syria, where they began an assault on a militant compound culminating in a retreat by Baghdadi into an underground hideaway. There, in a "dead-end tunnel," Trump said, the militant leader detonated an explosive vest, killing himself and three of what were believed to be his six children.

The high-risk operation brings a dramatic end to a years-long hunt for the man who spearheaded the Islamic State's transformation from an underground insurgent band to a powerful quasi-state that straddled two countries and spawned copycat movements across several continents.

At its peak, the Islamic State controlled an area the size of Great Britain, boasting a massive military arsenal and a formidable financial base that it used to threaten the West and brutalize those under its control. While the group gradually lost territory to U.S.-backed Syrian and Iraqi fighters, officials cautioned that it remains a potent insurgent force, even after Baghdadi's death.

Officials said U.S. intelligence in recent days tracked the militant leader, a one-time academic and veteran jihadist who spent a year in a U.S.-run prison in Iraq, to a site in Syria's Idlib province, a restive area near Syria's border with Turkey and home to an array of extremist groups.

Vice President Mike Pence, speaking to CBS, said he and Trump were first informed of the likelihood Baghdadi would likely be at the target site on Thursday. Trump authorized the mission on Saturday morning. Officials said two U.S. servicemembers were lightly wounded in the operation and that additional militants were killed, including two women identified as Baghdadi's wives who were wearing explosive vests.

The raid comes as the United States scrambles to adjust its posture in Syria in the wake of Trump's decision to curtail the U.S. military mission there. Trump faced widespread criticism, including from members of his own party, when he declared earlier this month that he would pull out nearly all of the approximately 1,000 troops in Syria amid a Turkish offensive against Syrian Kurdish troops who have been the Pentagon's main battlefield partner there. But evolving plans now call for a larger residual force that could mean a substantial ongoing campaign.

It also comes as the president faces impeachment proceedings over his role in withholding military aid to Ukraine and as the campaign for the 2020 presidential elections intensifies.

National security adviser Robert O'Brien, speaking to NBC, said it was "a good day for the United States for our armed forces and for the president."

During his remarks, Trump thanked Syrian Kurdish forces and other nations, including Russia and Turkey.

Officials said the United States coordinated with Russia, which is an important backer of Syrian President Bashar al-Assad and operates air defense systems in Syria, to ensure the safety of U.S. personnel during the raid.

Trump described a harrowing operation that involved firefights before and after U.S. personnel, ferried under the cover of darkness in eight helicopters, touched down in Idlib.

He said the military had taken DNA samples from Baghdadi's remains and had quickly conducted tests to determine his identity. Nearly a dozen children were removed from the site, the president said. It's unclear where they were taken.

"Baghdadi was vicious and violent, and he died in a vicious and violent way, as a coward running and crying," he said. Baghdadi's actions during the operation could not be immediately verified.

One official, who spoke on the condition of anonymity to discuss operational details, said that troops from Delta Force, an elite military unit, conducted the operation with support from the CIA and Kurdish forces. The official said Baghdadi had been located in large part thanks to the fact that U.S. intelligence agencies had intensified their focus on Idlib because of militants there with loose links to al-Qaida.

The DNA material needed to identify Baghdadi was voluntarily provided by one of his daughters, the official said.

Trump praised his military and intelligence officials for the operation, which he said he watched from the White House situation room on Sunday afternoon with Pence, Defense Sec. Mark Esper, Gen. Mark Milley, chairman of the Joint Chiefs of Staff, and other senior officials.

In describing the importance of Baghdadi's death, Trump named American citizens whose executions by the Islamic State first pulled the United States into a military operation against the group, including James Foley, Steven Sotloff and Peter Kassig. Pence said the Pentagon leadership had named the operation after Kayla Mueller, an American woman who died in Islamic State custody and whom U.S. officials have said was repeatedly raped by Baghdadi.

During the group's extremist reign, many more Iraqis and Syrians were killed or brutalized. Militants also enslaved women and children from Iraq's Yazidi minority.

The operation served as a reminder of the grim series of events set off by the rise of the Islamic State, and the sophisticated global propaganda and recruitment network that rise enabled. Among the high-profile acts of violence the group inspired outside its physical territory were the 2015 attacks in Paris and San Bernadino, California. The group also used its financial and political power to stand up potent foreign affiliates in places like Libya. The Pentagon continues to conduct attacks against self-branded Islamic State fighters in Afghanistan, Yemen and Somalia.

While Baghdadi, 48, a native of the Iraqi city of Samarra, was not the first leader of the evolving militant organization that eventually became the Islamic State, he oversaw its rise to global prominence in 2014 as it took advantage of instability and weak governance and, rolled across Iraq and Syria.

Despite publicly declaring an ambitious extremist vision in a high-profile address that same year, Baghdadi remained a distant, reclusive figure even to his supporters. In recent years, he has attempted to usher the organization into a renewed underground phase, urging followers in an audio message issued last month, to launch attacks against security forces and to attempt to break imprisoned brethren out of jail.

After his death a number of U.S. allies highlighted their role in contributing to Saturday's mission.

A senior official from Iraq's intelligence service, speaking on the condition of anonymity to discuss intelligence matters, said the arrests and interrogation of a number of people close to Baghdadi yielded up his location, which was provided to the Americans. He confirmed the location raided Saturday was the one that his service had discovered.

Meanwhile, the Kurdish-led Syrian Democratic Forces (SDF), whose troops have fought alongside the United States in Syria, indicated that they too had provided intelligence for the operation.

"For five months there has been joint intel cooperation on the ground and accurate monitoring, until we achieved a joint operation to kill Abu Bakir al-Bagdadi," its commander, Gen. Mazloum Abdi said on Twitter.

Trump has recently been accused of abandoning the Kurds following a decision to pull back most of the U.S. forces in northern Syria that had provided a deterrent against the Turks across the border. Officials on Sunday suggested Baghdadi's death would not affect U.S. plans to curtail the military mission in Syria.

The raid targeting Baghdadi took place outside the area where the U.S. military - which began airstrikes on Islamic State positions in Syria in 2014 and established a ground mission the following year - has focused its campaign in recent years. There have been occasional U.S. attacks on militant targets in Idlib, including an airstrike last month.

Pentagon officials have warned that the Islamic State could use the recent upheaval in northern Syria as an opportunity. Last week, Esper acknowledged that more than 100 fighters had escaped from Kurdish-run prisons as Turkish-backed forces have battled the SDF, which Ankara considers a terror group.

Faysal Itani, a scholar at the Atlantic Council, said that the Islamic State's militant activities had not been enabled by any special powers of Baghdadi himself, suggesting its potential to rise once more.

"ISIS' success is rooted in state failures, sectarian divides, military and intelligence experience drawn from the Baathist security state it emerged from, and an ideology that is coherent and, for some, compelling," Itani said, referring to the Baath party of Saddam Hussein, the former leader of Iraq.

- - -

This article was written by Missy Ryan and Dan Lamothe, reporters for The Washington Post.

The Washington Post's Liz Sly in Los Angeles, Souad Mekhennet in Germany, Sarah Dadouch in Beirut, Kareem Fahim in Istanbul, Mustafa Salim in Baghdad and Shane Harris, Joby Warrick and Ellen Nakashima in Washington contributed to this report.