The group's leader, Abu Bakr al-Baghdadi, is believed to be hiding in the desert near the frontier.

It said he was particularly motivated by seeing a video in which Abu Bakr al-Baghdadi, who led the campaign by ISIS to seize territory for a self-proclaimed caliphate within Iraq and Syria, exhorted Muslims in the United States and elsewhere to support

ISIS leader Abu Bakr al-Baghdadi, who in 2014 declared in Mosul the founding of a new Islamic caliphate in Iraq and Syria, released an audio recording on Sept. 28 indicating he was alive following several reports of his death.

ISIS leader Abu Bakr al-Baghdadi, who in 2014 declared in Mosul the founding of a new Islamic caliphate in Iraq and Syria, released an audio recording on Sept. 28 indicating he was alive following several reports of his death.

US Role After Mosul Fight The trip to Iraq comes as Iraqi security forces engage in fierce, house-to-house fighting to retake Mosul, ISIS's last major stronghold in Iraq and the city where leader Abu Bakr al-Baghdadi declared a caliphate nearly three

Almost exactly three years ago, the ultra-hardline group's leader Abu Bakr al-Baghdadi declared from Mosul a "caliphate" over adjoining parts of Iraq and Syria.

Islamic State leader Abu Bakr al-Baghdadi has called for the replacing of the Middle East's crumbling nations with a transnational regional power.

He posted on Facebook about his "Alliance to [ISIS leader] Abu Bakr Al Baghdadi." After the shooting took place, Mateen paused and searched for "Pulse Orlando" and "shooting." Later, he made calls to 911 and a television station.

During several calls with police during the attack, Mateen identified himself as an Islamic soldier and pledged his allegiance the ISIS terrorist group and its leader, Abu Bakr al-Baghdadi, according to an FBI transcript.

He added that the man pledged allegiance to ISIS leader Abu Bakr al-Baghdadi during negotiations prior to the police assault, adding he was answering an ISIS call to "kill infidels."

"The group appears to be a long way from realizing the vision that Abu Bakr al-Baghdadi laid out when he declared the caliphate two years ago in Mosul," Iraq, Brennan said.

The fall of Mosul would, in effect, mark the end of the Iraqi half of the "caliphate" that ISIS leader Abu Bakr al-Baghdadi declared in a speech from an historic mosque in the Old City three years ago, covering parts of Iraq and Syria.

In late June 2014, he formally declared the establishment of a caliphate, or Islamic state, stretching across parts of Syria and Iraq, under the leadership of Abu Bakr al-Baghdadi, and demanded allegiance from Muslims worldwide.

Police found a handwritten pledge of allegiance to Islamic State leader Abu Bakr al-Baghdadi inside the purse of Ines Madani.

Jim Sciutto, CNN's chief national security correspondent, says that Malik allegedly posted a note of support for ISIS leader Abu Bakr al-Baghdadi, under a different account name on Facebook.

It said the man opened fire from an automatic rifle and also detonated hand grenades in "revenge for God's religion and in response to the orders" of ISIS leader Abu Bakr al-Baghdadi.

Twitter/screenshot They also Photoshopped a duck head on leader Abu Bakr al-Baghdadi.

In 2014, he pledged allegiance to ISIS leader Abu Bakr Al Baghdadi, authorities added. In January, he wrote to President Obama, saying "we are coming to America and know that we will sever your head in the White House."

In late June 2014, he formally declared the establishment of a caliphate, or Islamic state, stretching across parts of Syria and Iraq, under the leadership of Abu Bakr al-Baghdadi, and demanded allegiance from Muslims worldwide.

. … Do not think that we have forgotten about you," said the terror group's leader Abu Bakr al-Baghdadi. "God caused the Jews of the world to gather in Israel, and the war against them has become easy. 

After the death of bin Laden in May 2011, ISIS's new leader Abu Bakr al-Baghdadi began to have tactical issues with the leader of al-Qaeda, Emir Ayman al-Zawahiri.

The leaked document was written shortly after the group's leader, Abu Bakr al-Baghdadi, declared a "caliphate" in the terrority the organization controls in both countries.

It was from the mosque that ISIS leader Abu Bakr al-Baghdadi announced himself to the world for the first time as the "caliph", or ruler of all Muslims, on July 4, 2014. Mosul's population at the time was more than 2 million.

Iraqi intelligence sent a dispatch saying the group's leader, Abu Bakr al-Baghdadi, had ordered an attack on coalition countries fighting against them in Iraq and Syria, as well as on Iran and Russia, "through bombings or assassinations or hostage taking

The ISIS group captured Mosul during a lightning advance across northern Iraq in 2014, and ISIS leader Abu Bakr al-Baghdadi announced the formation of a self-styled caliphate from the pulpit of a Mosul mosque.

He pledges allegiance to Abu Bakr al-Baghdadi, the Islamic State leader, and threatens an attack against Canada. Driver had been under the spotlight for at least a year, as authorities believed he was a threat because he could help terror groups.

They included seemingly random posts about serial killer Ted Bundy, a collection of selfies, the top-secret Area 51 Cold War test site and photos of Iranian Supreme Leader Ayatollah Khamenei and Islamic State group leader Abu Bakr al-Baghdadi.

#DenisCuspert #ISIS pic.twitter.com/0qYJm1pnE0 — DW (English) (@dw_english) February 10, 2015 According to the State Department: Cuspert has pledged an oath of loyalty to ISIL leader Abu Bakr al-Baghdadi and appears to serve as an ISIL recruiter

Abu Bakr al-Baghdadi is dead. Mr.

"stop bombing" Syria and Iraq, warned of future violence in the coming days and at one point pledged allegiance to Abu Bakr al-Baghdadi, the leader of the Islamic State, the FBI said.