The batteries of the walkie-talkie bombs were loaded with a highly explosive compound that is almost impossible to detect, Lebanese sources reveal

The batteries of the walkie-talkies used by the Lebanese armed group Hezbollah that exploded this week were loaded with a highly explosive compound known as PETN, a Lebanese source familiar with the device’s components said.

The astonishingly coordinated and devastatingly effective attacks, widely seen as the work of Israel’s Mossad secret service, wounded thousands of militants, not to mention many civilians, on Tuesday and Wednesday.

Security officials and experts theorized earlier this week that Israeli spies had managed to infiltrate the supply chain and place a small amount of explosives inside the communication devices before they were delivered to Lebanon sometime this spring.

Now, the assessment of the Lebanese security source seems to have confirmed the speculation.

The source told Reuters that the way the explosive material was embedded in the batteries of Halcyon communications devices made it extremely difficult to detect.

PETN (pentaerythritol tetranitrate) is a widely used chemical explosive that shares many similarities with nitroglycerin.

It is typically used in detonating cords and directional charges, and is used in military operations in the form of weapons such as the plastic explosive Semtex.

The substance has two main properties that make it a very attractive option for both military and industrial use.

First, PETN has an extremely high detonation velocity, capable of exploding the shrapnel contained in the munitions at around 8,000 meters per second.

Such force means that PETN explosives can create a devastating effect, shattering their targets and also causing a powerful concussive effect.

Secondly, it is a relatively stable and very reliable substance. If properly preserved and stored, it can be used in all kinds of conditions..

Ironically, it was Hezbollah’s fears that modern technology posed a security risk that allowed Israel to target the group’s members with PETN.

Hezbollah Secretary-General Hassan Nasrallah said in February that smartphones, which are much harder to tamper with, were “more dangerous than Israeli spies.”

In a televised speech on February 13, Nasrallah sternly ordered his followers and supporters to smash, bury or lock their phones in an iron box, so that they could be replaced with pagers and radios.

The exact method by which the pagers were sabotaged remains unverified.

But a senior Lebanese security source told Reuters earlier this week that the booby-trapped devices distributed to thousands of Hezbollah members appeared to have been modified “at production level”.

“The Mossad inserted a plate inside the device containing explosive material that receives a code. It is very difficult to detect it by any means. Even with any device or scanner,” the source said.

Thousands of pagers and radios exploded on Tuesday and Wednesday when a coded message was sent to them.

The code appears to have caused the devices to beep or vibrate, prompting the user to press a button to cancel the alert, thereby activating the detonator.

Munitions experts said videos and eyewitness descriptions of the explosions appeared to support the idea that the devices were loaded with a small amount of high explosives.

A former British Army bomb disposal officer explained that an explosive device has five main components: a container, a battery, a detonating device, a detonator and an explosive charge.

“A pager already has three of those,” said the former officer, who spoke on condition of anonymity because he now works as a consultant with clients in the Middle East.

‘You would only have to add the detonator and the charge.’

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one incorporating an extremely small, highly explosive charge,” added Sean Moorhouse, a former British army officer and explosive ordnance disposal expert.

Security experts, regional analysts and military officials have almost unanimously pointed the finger at the Mossad and elements of the Israeli military, arguing that no other actor has the capability or motive to carry out such an attack.

Former Israeli intelligence official and regional analyst Avi Melamed told MailOnline: ‘Hezbollah returned to these devices thinking they would be safer for its fighters rather than phones that could be targeted by GPS.

‘In a widespread attack, with significant operational and psychological ramifications, very low-tech devices were used against them, deepening the stress and shame of their leaders.

‘The characteristics of the incident indicate the use of advanced technologies for disruption, takeover of the communication system and remote operations with an exceptionally high level of synchronization.

“The accumulated evidence suggests that the devices were tampered with in advance, not by malicious software. While Israel has not, and is unlikely to, take responsibility for the attack, there is no doubt in the regional discourse that Israel is behind it.”

Professor Andreas Krieg, a Middle East expert and senior lecturer at the School of Security Studies at King’s College London, said: “Regardless of how they obtained it or how they acquired this device, Israel has been able to infiltrate and compromise the supply chain.

‘Tampering with a physical device that was then distributed throughout the Hezbollah network is quite extraordinary because it requires coordination and probably requires someone inside who is cooperating.

‘If we look at the broader picture that has been emerging over the past few months, it appears that the Israelis have been fairly successful on the intelligence front in engaging their enemies, given who they have targeted and how precisely they have been able to do so.

If you look at the way Hamas leader Ismail Haniyeh was killed in Tehran, for example, that suggests that Hamas, Hezbollah and the Iranians are heavily infiltrated; there may also be certain people who cooperate with the Israelis.

The Mossad has a reputation for carrying out sophisticated operations.

He is blamed for a series of cyber attacks and is suspected of being behind the assassination of a top Iranian scientist with a remote-controlled machine gun.

But the pager attack would constitute one of the agency’s most complex and audacious operations, and represents “easily the biggest counterintelligence failure Hezbollah has had in decades,” according to Jonathan Panikoff, a former deputy U.S. government national intelligence officer for the Middle East.