(CNN) ISIS leader Abu Bakr al-Baghdadi is believed to have been killed in a raid conducted by the US military in northwest Syria on Saturday, according to a senior US defense official and a source with knowledge. The final confirmation is pending while DNA and biometric testing is conducted, both sources tell CNN.

The defense official said it appears that Baghdadi detonated a suicide vest during the raid.

The raid was carried out by special operations commandos, a source familiar with the operation told CNN.

The CIA assisted in locating the ISIS leader, the defense official said. Iraqi forces also gave "important information" in the operation, Maj. Gen. Tahseen al-Khafaji, a spokesperson for the Iraqi Joint Operations told CNN.

The Kurdish-lead Syrian Democratic Forces (SDF) tweeted that there was a "successful" joint operation with the US -- but did not specifically name what that operation was or give any further details.

"Successful & historical operation due to joint intelligence work with the United States of America," Mazloum Abdi, SDF General Commander tweeted Sunday.

ISIS leader Abu Bakr al-Baghdadi appears in this video recording posted on the Internet on July 5, 2014.

Newsweek first reported that Baghdadi was believed to have been killed.

President Donald Trump is scheduled to make a major announcement Sunday at 9 a.m., White House deputy press secretary Hogan Gidley announced. An administration official tells CNN that the announcement is foreign policy related.

The Pentagon did not immediately respond to a request for comment.

White House officials were at the White House late Saturday evening in preparation for an announcement. One official told CNN it would be held in the Diplomatic Reception Room.

Trump stoked speculation when he tweeted Saturday evening "something very big has just happened!"

Feared preacher of hate

Baghdadi, the leader of the terror group, is believed to have been in hiding for the last five years. In April, a video was published by the ISIS media wing al-Furqan that showed a man purporting to be Baghdadi. It was the first time Baghdadi had been seen since July 2014, when he spoke at the Great Mosque in Mosul.

A report in 2015 claimed he was badly wounded -- even bedridden -- by a US strike, yet the Pentagon never confirmed this injury. More reports suggested he was wounded again in 2017, as US-backed and other forces closed in on ISIS' territory in Syria.

In February 2018, several US officials said Baghdadi had been wounded in an airstrike in May 2017 and had to relinquish control of the terror group for up to five months because of his injuries.

Baghdadi became the leader of Islamic State of Iraq (ISI) in 2010. In 2013, ISI declared its absorption of an al Qaeda-backed militant group in Syria and Baghdadi said that his group will now be known as Islamic State in Iraq and the Levant (ISIL or ISIS).

Later that year Baghdadi's followers first swept into Raqqa. That began their ambitions in Syria, and led in June 2014 to the establishing of what they called an Islamic "caliphate," never short of ambition, but rarely showing enough sobriety or statehood to last for very long.

They had rules, an army, and briefly a currency, yet just over three years later were reduced to fighting for scraps of Mosul in Iraq and the object of a large offensive against their de facto capital in Raqqa.

ISIS' control of Mosul officially crumbled in July 2017, when Iraqi Prime Minster Haider al-Abadi declared that troops had recaptured the metropolis.