Who killed Hezbollah’s top commander in Syria?

Hezbollah’s most senior military official and the commander of the Lebanese Shiite group’s forces in Syria has been killed, the group announced on Friday.

Mustafa Badreddine, a 55-year-old Lebanese national, began his career as a bomb maker and rose through the ranks to play a crucial role in Hezbollah’s operations in Syria, where the group has fought alongside President Bashar al-Assad in his bid to crush an uprising against him.

UPDATE: Since this article was published, Hezbollah has released a statement blaming Syrian rebel groups for the death of Mustafa Badreddine.

The statement reads: "Investigations have showed that the explosion, which targeted one of our bases near Damascus International Airport, and which led to the martyrdom of commander Mustafa Badreddine, was the result of artillery bombardment carried out by takfiri groups in the area.” Takfiri is a word used by Hezbollah in reference to hard-line Sunni extremist groups.

Badreddine was listed as a “Specially Designated Global Terrorist” by the US Treasury in 2012, and has been linked to a number of spectacular terrorist attacks throughout his life. He was convicted of a bomb attack on the US Embassy in Kuwait in 1983, and is suspected of involvement in preparing a massive truck bomb that targeted US barracks in Beirut in the same year, killing 241 US service members.  

Over the last three years, Hezbollah has been credited by some with turning the tide of the war in Assad’s favor — Badreddine has led those efforts since the beginning. In a statement announcing sanctions against him, the US said the commander led Hezbollah forces in a key 2013 battle against Syrian rebels in the mountainous region that straddles the Lebanon-Syria border. “Since September 2011, strategic coordination was handled between Assad and Hizballah leader Hassan Nasrallah on a weekly basis, with Badr Al Din accompanying Nasrallah during the meetings in Damascus,” the statement said.

It is unclear who is responsible for Badreddine’s death, or how exactly he met his end, but Hezbollah said in a statement that he was killed in an explosion near Damascus airport, and that several others were injured.

Nawar al-Saheli, a member of parliament for Hezbollah, claimed that Israel was behind the attack, and promised a response.

"This is an open war and we should not pre-empt the investigation but certainly Israel is behind this,” he told Lebanese TV station al-Manar, which is owned by Hezbollah. "The resistance will carry out its duties at the appropriate time."

But other pro-Hezbollah media outlets have so far refrained from explicitly blaming Israel for the attack, as they did promptly on previous occasions. Israel has neither confirmed nor denied being behind the attack, as is customary.

Israel has targeted senior Hezbollah figures and weapons convoys in Syria numerous times since the conflict began, most notably with the killing of Jihad Mughniyeh, the son of Badreddine’s predecessor Imad Mughniyeh, in January last year. (The elder Mughniyeh was assassinated in Damascus in 2008, in an operation that Hezbollah, Syria and Iran blamed on Israel.)

Hezbollah responded to the younger Mughniyeh’s death in 2015 by striking a military vehicle on the Israel-Lebanon border with an anti-tank missile, killing two Israeli soldiers.

Whoever carried out the attack that killed Badreddine, the commander’s death is a serious blow to Hezbollah, which has devoted significant resources and manpower to support the Syrian government in its fight against a largely Sunni uprising.

Prior to his involvement in Syria, Badreddine was named in a United Nations tribunal as a key suspect in the assassination of former Lebanese Prime Minister Rafik Hariri.

Hezbollah justifies its engagement in the Syrian civil war as being necessary to protect Lebanon from jihadist groups that might eventually cross the border. The group has fought major battles with the al-Qaeda offshoot Jabhat al-Nusra and the Islamic State on the Lebanese border. Before the war, Syria was a key ally of Hezbollah, providing it with the means to transport Iranian weaponry for fighting its arch enemy, Israel.

Hezbollah’s efforts to defend Assad have taken a toll on the group, which is estimated to have lost around 1,200 fighters in Syria, from a force of around 12,000.

If it emerges that Israel is behind Badraddine's killing, it is possible that Hezbollah will retaliate in some form. But Hezbollah would likely aim to minimize the risk that its retaliation would trigger a larger Israeli response.

An Israeli invasion of Lebanon in 2006, sparked by the kidnapping of four Israeli soldiers by Hezbollah fighters on the border between the two countries, left much of Lebanon’s infrastructure destroyed and more than 1,000 Lebanese civilians killed.

During that conflict, Hezbollah was able to inflict heavy damages on Israeli troops and fire thousands of rockets deep into Israel.