IRBIL, Iraq--As an array of local and international forces close in on Islamic State's last redoubts in Syria and Iraq, the whereabouts of the extremist group's secretive leader remain a mystery.
A media outlet linked to the Syrian military reported Friday that Abu Bakr al-Baghdadi had been spotted in the eastern town of Bukamal during a recent offensive to recapture Islamic State's last urban stronghold in Syria. But al-Baghdadi sightings have been reported before. So has his death. None of it has ever been confirmed.
The latest claim was also carried by a media unit operated by the Lebanese Shiite militia, Hezbollah, whose forces took part in the operation in support of Syrian President Bashar Assad.
No further details were provided, however, including what the source was for the purported sighting.
The capture or killing of al-Baghdadi -- who has a $25-million U.S. bounty on his head -- would be another significant blow to Islamic State, which has lost more than 90 percent of the territory it once controlled in Syria and Iraq following multiple offensives on both sides of the border.
But Syrian opposition activists with contacts in the region were skeptical that al-Baghdadi was holed up inside Bukamal, where fierce clashes were reported Friday. They suggested that pro-Assad forces were trying to divert attention from an Islamic State counterattack that reclaimed as much of half of the border town after the government declared it liberated Thursday.
"This is propaganda," said Rami Abdul-Rahman of the supposed al-Baghdadi sighting. Abdul-Rahman is head of the pro-opposition Syrian Observatory for Human Rights, based in Britain. "If it's true, let them show the video."
The U.S.-led coalition fighting Islamic State in Syria and Iraq said it did not have any "verifiable information" concerning al-Baghdadi's whereabouts. Neither the coalition nor the Syrian militias it supports are operating in the immediate vicinity of Bukamal, it said in an email.
Rumors about al-Baghdadi have swirled since his fighters swept across Syria and Iraq in 2014, capturing about a third of both countries.
The cleric, known primarily through grainy mug shots and audio messages exhorting fellow Sunnis Muslims to rise up against "infidels," is believed to have made only one public appearance. In July 2014, he delivered a sermon at the Grand Mosque in the northern Iraqi city of Mosul in which he declared himself leader of a new caliphate, or Islamic state, stretching from Aleppo in Syria to Diyala in Iraq.