What do we know of the killing?

An initial report by Lebanon's al-Mayadeen TV said that Badreddine, 55, had died in an Israeli air strike. But a later statement by Hezbollah on al-Manar's website did not mention Israel. Israel's government traditionally refuses to comment on such deaths and has done so again.

Mustafa Amine Badreddine was involved in Hezbollah military operations for years

Hezbollah deputy leader Sheikh Naim Qassem spoke at the funeral, flanked on his right by leader Hassan Nasrallah

Hezbollah says it will soon report on who it believed killed Badreddine

But Israel has been accused by Hezbollah of killing a number of its fighters in Syria since the conflict began.

The group was established in the wake of the Israeli occupation of Lebanon in the early 1980s, and has called for the "obliteration" of Israel.

Asked who might have carried out the attack, Hezbollah deputy leader Sheikh Naim Qassem said that, within hours "we will announce in detail the cause of the explosion and the party responsible for it", adding there were clear indications of those responsible.

One Hezbollah MP in Lebanon, Nawar al-Saheli, said: "This is an open war and we should not pre-empt the investigation but certainly Israel is behind this. The resistance will carry out its duties at the appropriate time."

Yaakov Amidror, a former national security adviser to Israeli PM Benjamin Netanyahu said: "We don't know if Israel is responsible for this. 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."

However, any of the armed groups seeking to overthrow President Bashar al-Assad might have have sought to kill the man co-ordinating Hezbollah military activities.

Reuters news agency quoted White House spokesman Josh Earnest as saying that there were "no US or coalition aircraft in the area where he was reported to be killed".

What is Badreddine's background?

Born in 1961, Badreddine is believed to have been a senior figure in Hezbollah's military wing. He was a cousin and brother-in-law of Imad Mughniyeh, who was the military wing's chief until his assassination by car bomb in Damascus in 2008.