This picture taken on August 7 shows a blown-up ship that was thrown onto the land at Beirut Port three days before by a massive blast that shook the Lebanese capital. Photo: Joseph Eid / AFP

Israel was “clearly” responsible for the explosion that shattered Beirut on August 4, killing more than 170 people, wounding thousands and destroying swaths of the city, Lebanese former interior minister Nohad Machnouk told a press conference Wednesday.

“This operation in Beirut was carried out by Israel in a clear and explicit manner,” Machnouk said, adding: “It is clear we are looking at a crime against humanity, and therefore no one dares to claim responsibility for it.”

Israel denied responsibility almost immediately after the blasts, via unnamed officials.

Machnouk, who was appointed interior minister in 2014 and again in 2016, is the first senior Lebanese politician to point the finger at Israel. He belongs to the Future Movement, which opposes Hezbollah.

Hezbollah leader Hassan Nasrallah and his ally Lebanese President Michel Aoun have raised the possibility of “sabotage” but notably have not named Israel as a suspect, despite weeks of spiking confrontations along the border and in Syria, and a recent spate of mysterious explosions in Iran.

If Israel were to be determined responsible, Lebanese sources say, it would necessitate an equivalent reply from Hezbollah, which would prompt a devastating war not in the interest of the party or its allies.

Blaming an Israeli attack would also provoke further investigations into what exactly was being targeted, and raise questions for all Lebanese factions, including Machnouk’s, as to how they allowed the port to be militarized.

Lebanon’s top security officials have told the public a 2,750-tonne store of ammonium nitrate, confiscated under murky circumstances by Port of Beirut Customs in 2013 and stored in a poorly-secured warehouse until last week, was the source of the final blast.

Machnouk on Wednesday claimed more than half of the original amount had been stolen.

“What judge would dare to declare that the size of the explosion was 1,350 tonnes, not 2,750?” he demanded.

“Where did the remaining 1,400 tonnes disappear?”

As to the cause of the initial blast, which exploded the ammonium nitrate, Lebanese officials have proposed that a welder making building repairs sparked a fire, which then set off a nearby depot of fireworks.

“The cause of the first fire/explosion is still an unanswered question,” a US official told Asia Times on condition of anonymity.

While there have been reports the initial fire may have been due to negligence, the source said he had not yet seen “actual evidence to support or confirm that” and that “other alternatives” are possible.

A US military explosives expert who has worked closely with the Lebanese army told Asia Times on condition of anonymity that according to his contacts among the Lebanese armed forces, the explosion was an “act of sabotage” against the hangar in question, which was allegedly holding not only ammonium nitrate, but short-range missiles.

Machnouk on Wednesday alleged that missile remnants had been discovered in the rubble of the blast, and accused judicial authorities overseeing the investigation of keeping this alleged finding under wraps.

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Alison Tahmizian Meuse

Alison T Meuse is the Asia Times Middle East editor and correspondent.