Jim Michaels

USA TODAY

WASHINGTON — The Pentagon has been unable to confirm reports that the leader of the Islamic State was injured or killed this weekend, but his loss wouldn't necessarily spell the end of the organization.

"I'm not aware of any successful decapitation strike that resulted in the end of an insurgency," said Ben Connable, a retired Marine Corps intelligence officer now at RAND Corp.

Perhaps few militant leaders know that more than Abu Bakr al-Baghdadi himself, who replaced Abu Musab al-Zarqawi as head of al-Qaeda in Iraq when Zarqawi was killed in a 2006 U.S. airstrike.

At the time, there was hope that Zarqawi's death meant the decline of al-Qaeda in Iraq. Instead, al-Baghdadi held the militant organization together despite U.S. pressure and later transformed it into the Islamic State after breaking from al-Qaeda. Today, the militant group represents the leading threat to Middle East stability and has triggered a major U.S. air campaign.

Al-Baghdadi, believed to be in his 40s, has a $10 million bounty on his head.

"If he dies they would probably find a quick replacement," said Abdulkader Sinno, an Indiana University professor who has written about insurgency organizations.

The loss of a central leader could possibly lead to infighting among regional factions, but that wouldn't end the violence fueled largely by sectarian conflicts, Connable said.

Reports of al-Baghdadi's death or wounding were triggered by Iraq's Defense Ministry over the weekend that the Islamic State leader appeared to have been injured in an airstrike. On Monday, the Pentagon and U.S. Central Command said they could not confirm those reports but were still looking into them.

There are conflicting reports over what happened.

U.S. Central Command said it launched an airstrike over the weekend on a presumed meeting of Islamic State leaders near Mosul. Al-Baghdadi was not being tracked, but aircraft struck when they noticed what appeared to be a convoy of top militants, the Pentagon said.

Iraq's Defense Ministry, however, said al-Baghdadi was wounded during an attack in al-Qaim, a border town in western Iraq. The U.S. military launched attacks there over the weekend, but the airstrikes did not target anything that resembled a meeting of top militant leaders.

Al-Baghdadi started his career as a foot soldier in al-Qaeda in Iraq, the militant group fighting the American presence in Iraq after the U.S.-led invasion to topple Saddam Hussein in 2003.

He was detained briefly by U.S. forces in 2004, but at the time he was not heavily involved in al-Qaeda and was released.

After Zarqawi's death in 2006, he was positioned to assume the top leadership of the organization, partly because so many other leaders had been killed or captured. By 2008, however, he was running a regional bombing network for al-Qaeda in Iraq.

"He's got good religious credentials and is charismatic," Connable said about al-Baghdadi. "Those things matter."

Al-Baghdadi has kept a low profile, unlike his predecessor, Zarqawi, who made regular videos and issued proclamations.

The fact that he was captured by Americans earlier may have made him more cautious, Sinno said. "He knows not to make a mistake," Sinno said.

Al-Baghdadi's years of experience fighting Americans may have honed his skills as an insurgent leader. "That is pretty good training, if you can survive it," Sinno said.