Video Purportedly Shows Islamic State Leader

A man claiming to be the self-appointed caliph of the Islamic State jihadist group made what is thought to be his first taped appearance in a video that circulated on social media Saturday.

Previously there were only two known images of the notoriously elusive Abu Bakr Al Baghdadi.

But Mr. Baghdadi’s appearance in the high-quality video, in which he demanded that Muslims swear allegiance to his recently announced caliphate, looked set to further strengthen the jihadist bona fides of a militant leader whose power and strength has already eclipsed that of older militant groups such as al Qaeda.

Mr. Baghdadi’s Islamic State seized huge parts of northern and western Iraq after staging a well-organized assault from the northern city of Mosul on June 10.

The group was known as the Islamic State of Iraq and al Sham, or ISIS, until the cleric declared a caliphate on June 29 through a spokesman in a recorded audio file.

Much of the speech and its presentation appeared to be a conscious attempt to connect Mr. Baghdadi to historical caliphs who ruled Islamic empires.

“I am the wali who presides over you, though I am not the best of you, so if you see that I am right, assist me,” he said, using an Islamic term for leader while speaking from an ornate pulpit at Mosul’s Nour al Din Mosque on Friday. “If you see that I am wrong, advise me and put me on the right track, and obey me as long as I obey God in you.”

The authenticity of Saturday’s video, as well as the location and time at which it was shot, was still unclear on Saturday.

But the man who claims to be the caliph in the images bears a strong resemblance to known images of Mr. Baghdadi.

The heavily bearded Mr. Baghdadi wore a black turban and a black abaya—a costume that seemed to mimic the style of the Abbasid caliphs who ruled much of the Islamic world from Baghdad in the eighth century, according to Hassan Hassan, an expert on Islamist movements at the Abu Dhabi-based Delma Institute, over his Twitter account.

“Baghdadi had to make a move like this, making a public appearance after announcing himself caliph,” said Aymann Jawad Al Tamimi, a researcher on jihadist movements and a fellow at the Philadelphia-based Middle East Forum.

As opposed to Osama bin Laden and Aymen al-Zawahiri, whose statements would be released several days after being made and would show the al Qaeda leaders in secluded forests or bland rooms without any objects to identify their location, Mr. Baghdadi’s public appearance at Mosul’s main mosque appeared to be intended as a statement about his authenticity as an Islamic leader and as a slight to the Iraqi and American governments that have been hunting him for years.

“Baghdadi’s project is already more successful than bin Laden or Zawahiri’s. Bin Laden had to attach himself to the Taliban in Afghanistan to be part of a state. Baghdadi has created a state by himself,” said Mr. Tamimi. “This has been taken to the next level.”