What is known about the blasts in Hezbollah pagers

Pagers used by Hezbollah, an armed group, to communicate dramatically burst almost simultaneously across the country on Tuesday, inflicting thousands of injuries.
There were about 2,800 injuries, many of them serious, and at least nine fatalities.
Although Israel is Hezbollah’s enemy, it is unknown how the attack, which appears to have been very sophisticated, happened. So far, no comments have been made by Israeli officials.

Where and when did it take place?
At approximately 15:45 local time (13:45 BST) on Tuesday, there were explosions in Beirut, the capital of Lebanon, as well as in other parts of the nation.

Witnesses saw smoke emerging from people’s pockets and heard what sounded like gunshots and fireworks followed by little explosions. A man appeared to have an explosive in his trouser pocket while working at a retail till in one frame of CCTV footage.

The New York Times said that before exploding, the pagers received communications that seemed to emanate from Hezbollah’s leadership, citing US authorities. Rather, the source said that these messages appeared to activate the gadgets.

After the initial explosions, there were more explosions for about an hour, according to Reuters. Numerous patients started showing up at hospitals all around Lebanon shortly after, and witnesses reported seeing scenes of widespread chaos.

Why did the pagers blow up?
The magnitude of Tuesday’s attack has shocked analysts, who point out that Hezbollah takes pride in its security protocols.
Some speculated that the devices may have exploded due to overheating pager batteries caused by a cyberattack. An action of that kind would be unheard of.

However, a lot of specialists disagree, pointing out that the explosion film is incompatible with the batteries overheating.
Alternatively, other researchers argue that there was a greater chance of a supply chain attack, where the pagers were altered with either during manufacturing or during transit.

The cyber-security community is becoming increasingly concerned about supply chain assaults as a result of several high-profile events in which hackers gained access to items during development.

However, software is typically the only target of these attacks. Attacks on the hardware supply chain are much less common since they require physical access to the device.
Had this been a supply chain attack, there would have been a massive operation to surreptitiously alter the pagers in some way.
The pagers were loaded with a small quantity of explosives months before the devices were brought into Lebanon, according to security officials there. One former British Army explosives expert, who wished to remain anonymous, told the BBC that he thought the weapons might have been activated by a remote signal at that point.