The Lebanese militant group Hezbollah says one of its top commanders was killed in a "huge blast" in Syria.
The explosion that killed Mustafa Badreddine, 55, happened near the Damascus International Airport in Syria's capital, and the group says it is investigating "whether it was a result of an airstrike or a rocket attack," according to a statement on its official media outlet, al-Manar.
It wasn't immediately clear who was responsible for the attack.
As NPR's Alison Meuse tells our Newscast unit, "Hezbollah fights along with Iran to support the Assad regime in Syria." The militants are seen as an important force behind Syrian President Bashar al-Assad's continued grip on power during the ongoing war.
Badreddine is believed to be responsible for the group's extensive military operations inside Syria since 2011, along with numerous other attacks. According to the U.S. Treasury Department, which has sanctioned Badreddine, his responsibilities included moving the group's fighters from Lebanon to Syria as well as leading a major group offensive.
The Hezbollah statement announcing his death quotes him as recently saying, "I won't come back from Syria unless as a martyr or a carrier of the banner of victory."
It's the highest-profile assassination from the ranks of the militant group since the 2008 slaying of top military commander Imad Mughniyeh, who was also killed in Damascus.
Alison adds, "Israel fears Hezbollah's growing influence in Syria and has carried out a number of strikes against its weapons convoys and commanders over the course of the war."
The office of Israeli Prime Minister Benjamin Netenyahu declined to comment on whether Israel was involved, The New York Times reports, "as did the Israel Defense Forces and the country's Foreign Ministry."
Haaretz reports that Yaakov Amidror, a former national security adviser to Prime Minister Benjamin Netanyahu, said, "This is good for Israel. Israel isn't always responsible for this. We don't know if Israel is responsible for this." He continues: "Remember that those operating in Syria today have a lot of haters without Israel."
Badreddine was also indicted for the 2005 assassination of former Lebanese Prime Minister Rafik Hariri, along with 3 other people. All are being tried in absentia.
During the prosecutor's opening remarks at that trial, held at the Special Tribunal for Lebanon near the Hague, lawyer Graham Cameron said Badreddine "passes as an unrecognizable and virtually untraceable ghost throughout Lebanon, leaving no footprint as he passes." In the hearing transcripts, he details how Badreddine lives off the radar:
"He has never been issued a passport. He has never been issued a driver's license. He is not the registered owner of any property in Lebanon. The authorities have no records of him entering or leaving Lebanon. No records are held by the Ministry of Finance which would reflect that he pays any taxes. There are no bank accounts in any of the banks or any of the financial institutions in the country in his name. There are no known photographs of him, at least none that would reveal how he looked during the material time. I expect the evidence to show that his alter ego, Sammi Issa, was assiduous in avoiding having his picture taken."
Matthew Levitt at the Washington Institute tells The Associated Press, "I really do think it will affect their morale. This is not just their commander in Syria. This is one of the most elite and uniquely pedigreed Hezbollah personalities."
A video posted on Twitter by BBC correspondent Quentin Sommerville showed crowds of supporters filling a street during Badreddine's funeral in Beirut.