Algerian militant Mokhtar Belmokhtar is seen in an undated picture from the U.S. Department of Justice. The U.S. military confirmed on Sunday that Belmokhtar was the target of a U.S. air strike in Libya. (Reuters)

A U.S. air strike in eastern Libya over the weekend appears to have killed Mokhtar Belmokhtar, an influential militant believed to have been the mastermind of a bloody hostage crisis in 2013, the Pentagon said on Monday.

Col. Steve Warren, a Defense Department spokesman, told reporters that the U.S. military’s initial assessment was that Saturday’s strike, in which two F-15 fighter jets dropped several 500-lb. bombs, killed the one-eyed, veteran jihadist.

“But we’re not prepared to confirm that, because we haven’t finalized our assessment,” Warren said. Because the U.S. military did not have personnel on the ground at the time of the strike, officials must rely on intelligence methods to determine whether Belmokhtar, who has erroneously been reported dead in the past, was in fact killed.

Belmokhtar, a former Algerian solider, was a long-time member of al-Qaeda in the Islamic Maghreb (AQIM), the group’s North African affiliate, but split off in 2012 to establish the Signed in Blood Battalion. Officials believe that group was behind the January 2013 siege of a gas complex in eastern Algeria, which killed almost 40 people, including three Americans.

Also known as Belaouer the One-Eyed and Mr. Marlboro, for his alleged involvement in cigarette smuggling, Belmokhtar fought in Afghanistan and in Algeria’s civil war.

The internationally recognized Libyan government, just one of two governments vying for legitimacy in Libya’s deepening civil conflict, reported on Sunday that the U.S. strike killed Belmokhtar, 43, and a number of other militants.

Maj. James Brindle, another military spokesman, said the Obama administration’s legal basis for the strike, the first in Libya since the 2011 war that ousted former dictator Moammar Gaddafi, rested on a law that Congress passed in the wake of the Sept. 11, 2001, attacks.

While that law, known as an Authorization for the Use of Military Force, does not mention al-Qaeda by name, the U.S. government has subsequently interpreted the law to provide for attacks on that group and “associated forces.”

Brindle said that Belmokhtar “had a long history of leading terrorist activities as a member of AQIM and maintained his personal allegiance to al-Qaeda.”

Robert Chesney, a professor and associate dean at the University of Texas School of Law, said the legal justification for striking Belmokhtar appeared to be similar to that used in past U.S. operations against leaders of al-Shabab, the Somalian militant group.

In those instances, rather than declaring an intent to attack al-Shabab as an organization, the administration has linked targeted individuals to al-Qaeda, thus putting them within the reach of the 2001 congressional authorization.

That argument could be strengthened by several recent statements attributed to Belmokhtar in which he affirmed his allegiance to al-Qaeda leader Ayman al-Zawahiri.

“If you look at the fact patterns, it’s clear we’re especially interested in the leaders involved in targeting Westerners and foreigners, even if that’s not the main focus of their larger organization,” Chesney said.

Juan Zarate, a former senior counter-terrorism official who is now a senior advisor at the Center for Strategic and International Studies said that Belmokhtar remained a key militant “regardless of the label he was operating under.”

He said Belmokhtar also highlighted the potential for Libya, where political disputes and an abundance of arms have turned the country into lawless theater for numerous armed groups, to act as an incubator for militants who may target the West.

That could mean that “Libya is fair game for U.S. counterterrorism action,” Zarate said.

Katherine Zimmerman, a fellow at the American Enterprise Institute, said Belmokhtar had long been involved in contraband and kidnapping, but had left AQIM in part because he wanted to expand his militant scope beyond North Africa and the Sahel region.