But uncertainty still surrounds the U.S. airstrike in eastern Libya, and whether Mokhtar Belmokhtar was actually among the militants said to have been killed in the bombing.
Belmokhtar, an Algerian national, is also believed to have played a central role in the kidnapping of veteran Canadian diplomat Robert Fowler, who was working in Niger as a United Nations special envoy.
Fowler and his colleague, Louis Guay, were kidnapped in 2008 and held for more than four months before being freed.
Libyan officials say Sunday's airstrike hit a gathering of militants on a farm outside Ajdabiya, a coastal city about 850 kilometres east of the capital, Tripoli, but there were conflicting reports on how many died.
An initial assessment shows the bombing that targeted Belmokhtar was successful, and "post-strike assessments" were still underway Monday to determine whether the Algerian militant was killed, said Col. Steve Warren, a Pentagon spokesman.
"But we're not prepared to confirm that because we haven't finalized our assessment," he said, adding that the strike had hit a "hard structure."
Maj. Mohammed Hegazi, a military spokesman from Libya's internationally recognized government based in the east, also said tests were needed to identify the dead, which numbered at least 17, with their bodies badly burned. Among those killed were three foreigners — a Tunisian and two unidentified militants, he said.
Hegazi criticized his own government for rushing to confirm late Sunday that Belmokhtar was among the dead.
"I don't confirm or deny. We are waiting confirmation," he told The Associated Press by telephone. "It is not easy."
He said the raid was based on solid intelligence that indicated militants forced out of the eastern city of Benghazi by fighting there had taken refuge in Ajdabiya.
No civilians were killed, Hegazi said, adding that the militants took the fatally wounded Tunisian to a hospital in Ajdabiya, clashes erupted with local troops that left three soldiers dead.
In the airstrikes, two F-15 fighter jets had launched multiple 500-pound bombs, a U.S. official said, speaking on condition of anonymity because the official was not authorized to discuss details of the attack. Authorities say no U.S. personnel were on the ground for the assault.
A Libyan Islamist with ties to militants said the airstrikes missed Belmokhtar, but killed four members of a Libyan extremist group linked to al-Qaida, Ansar Shariah, in Ajdabiya. That group was tied to the Sept. 11, 2012, attack on the U.S. Consulate in Benghazi that killed Ambassador Chris Stevens and three other Americans.
The Islamist, who spoke on condition of anonymity for fear of reprisal in Libya, told the Associated Press that Belmokhtar wasn't at the site of the airstrike.
However, a news website that has previously carried statements from Belmokhtar said he was in Ajdabiya, meeting with affiliates. The Mauritanian website quoted informed sources in Libya as saying six people were killed in the raid, and a Tunisian and Yemeni were wounded.
Abdel-Basit Haroun, a security adviser to the eastern government, said a total of 29 people were killed in the airstrike, which hit a meeting of al-Qaida affiliates as they tried to "rearrange their ranks."
If Belmokhtar's death is confirmed, it would be a major success for U.S. counterterrorism efforts. He is one of the most-wanted militants in the region, with a $5 million reward for information leading to his capture, and it is not the first time authorities claimed to have killed him.
Believed to be 43 years old, Belmokhtar fought in Afghanistan and was reported to have lost his eye in combat. He was one of a number of Islamist fighters who have battled Algeria's government since the 1990s, later joining al-Qaida in the Islamic Maghreb, the group's North Africa branch.
He was also known as "Belaouer the One-Eyed," ''Abou al-Abbes" and "Mr. Marlboro," because he was accused of smuggling cigarettes through the Sahara and the Sahel region.
He formed his own group and led the January 2013 attack on Algeria's Ain Amenas gas complex that killed 37 hostages. Belmokhtar later emerged in Libya, and is believed to have been based in the western and southern parts of the country.
The U.S. filed terrorism charges against Belmokhtar in connection with the Algeria attack. Officials have said they believe he remained a threat to U.S. and Western interests. Belmokhtar had just split off from al-Qaida in the Islamic Maghreb to start his own franchise.
The charges filed against him by U.S. law enforcement officials included conspiring to support al-Qaida, use of a weapon of mass destruction and conspiring to take hostages.
The RCMP confirmed that Ali Medlej and Xris Katsiroubas, both of whom went to the same high school in London, Ont., were among the 29 dead terrorists found in the Algerian plant.
U.S. Attorney Preet Bharara had said Belmokhtar "unleashed a reign of terror years ago, in furtherance of his self-proclaimed goal of waging bloody jihad against the West."
Intelligence officials said Belmokhtar had essentially built a bridge between AQIM and the underworld, creating a system where various outlaws support each other and enrol youths.
He's been linked to terrorist attacks and the lucrative kidnapping of foreigners in the region.
Published reports have said Belmokhtar was the commander of the terrorist cell that kidnapped Fowler and Guay.
In May 2013, The Associated Press reported that it obtained an al-Qaida letter that suggested about $1 million was paid for the release of Fowler in Niger four years before.
In a book he published, Fowler said he did not know if a ransom was paid.
Libya has been plagued by chaos since the civil war in 2011, which drew in U.S. and European airstrikes that helped topple longtime dictator Moammar Gadhafi. He was killed by armed groups, which have since grown to roil the country in violence.
Recently, the internationally recognized government, backed by its own militias, has been forced out of Tripoli by Islamist militias and their affiliated politicians who set up their own government and parliament.
Associated Press Video journalist Sagar Meghani in Washington and Rami Musa contributed to this report.
--With Files from The Canadian Press