Mustafa Amine Badreddine, one of Hezbollah's highest ranking military commanders, has been killed in Syria.
While initial reports attributed the attack to a covert Israeli operation, signs show that Israel was not responsible for the strike.
A Hezbollah statement did not say when, where or how he was killed, though it cited Badreddine saying he would return from Syria, where he was stationed, either victorious or as "a martyr."
When asked by an interviewer on Israel Radio about possible Israeli involvement, cabinet minister Zeev Elkin, a close confidant of Prime Minister Benjamin Netanyahu, declined to comment.
Yaakov Amidror, a former national security adviser to Prime Minister Benjamin Netanyahu, said Badreddine's killing was good news for Israel but stopped short of saying Israel was responsible.
"This is good for Israel. Israel isn't always responsible for this. We don't know if Israel is responsible for this," he told Israel's Army Radio. "Remember that those operating in Syria today have a lot of haters without Israel."
"But from Israel's view, the more people with experience, like Badreddine, who disappear from the wanted list, the better," he added.
Describing Badreddine as "the great jihadi leader," Hezbollah announced his death in a statement early Friday, saying he "took part in most of the operations of the Islamic resistance since 1982."
Hezbollah's Al-Mayadeen network first reported that Badreddine, 55, was killed by an Israeli Air Force attack near Damascus' airport on Tuesday.
Local media has since stopped reporting that Israel had a hand in Badreddine's death.
Badreddine was said to have assumed the position of his brother-in-law, Hezbollah commander Imad Moughniyeh, who died in a 2008 assassination in Damascus also attributed to Israel. However, some dispute his official status as the group's military leader, saying he was only in charge of its operations in Syria, as Hezbollah has never publicly named a successor for Moughniyeh, whose son Jihad was also killed in Syria in an attack said to be Israel's doing.
Israel has previously been accused of striking targets in Syria belonging to the Lebanese group and, in April, Prime Minister Benjamin Netanyahu seemed to confirm Israel struck dozens of Syrian weapons shipments that were en route to Hezbollah.
A U.S. Department of the Treasury statement detailing sanctions against Badreddine last year said he was assessed to be responsible for the group's military operations in Syria since 2011, and he had accompanied Hezbollah leader Sayyed Hassan Nasrallah during strategic coordination meetings with Assad in Damascus.
For years, Badreddine masterminded military operations against Israel from Lebanon and overseas and managed to escape capture by Arab and Western governments by operating clandestinely.
According to a security official who spoke with Reuters, Badreddine was said to have led Hezbollah's ground offensives in the Syrian border town of al-Qusair in February 2013, a key battle in the group's attempt to aid the embattled Syrian regime.
Even before supposedly taking over the group's military operations in the country, Badreddine was considered a prominent Hezbollah commander, with an illustrious record of crimes and attacks ranging from claims he was the bomb maker behind the 1983 bombing of the U.S. Marines barracks in Beirut that killed 241 Americans, to his playing a key role in the assassination of former Lebanese Prime Minister Rafik Hariri, for which he was tried in absentia at the International Court of Justice in The Hague. Outrage at his role in the Hariri assassination might have prompted the group to move him away from Lebanon and into Syria.
Badreddine was also sentenced to death in Kuwait for his role in bomb attacks there in 1983. He escaped from prison in Kuwait after Iraq invaded the country in 1990 under the leadership of Saddam Hussein.
His release from jail in Kuwait was one of the demands made by the hijackers of a TWA flight in 1985, and of the hijackers of a Kuwait Airways flight in 1988.
Hezbollah's al-Manar TV said he would be buried at 5:30 P.M. in the southern suburbs of Beirut.
Reuters contributed to this report.
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