Deadly pager blasts expose a key weakness. Here's what we know

 Hundreds of pagers carried by Hezbollah members in Lebanon blew up nearly simultaneously on Tuesday in an unprecedented attack that surpasses a series of covert assassinations and cyber-attacks in the region over recent years in its scope and execution.

The Iran-backed militant group said the wireless devices began to explode around 3:30 p.m. local time in a targeted Israeli attack on Hezbollah operatives.

CNN learned that Israel was behind the attack, which was a joint operation between Israel’s intelligence service, the Mossad, and the Israeli military. The Lebanese government condemned the attack as “criminal Israeli aggression.”

Israel’s military, which has engaged in tit-for-tat strikes with Hezbollah since the start of the war with Iran-backed Palestinian militant group Hamas in Gaza last year, has refused to comment publicly on the explosions.

The pagers that exploded were new and had been purchased by Hezbollah in recent months, a Lebanese security source told CNN. The source did not provide any information on the exact date the pagers were bought or their model.

Experts say the explosions, unprecedented in their scale and nature, underscore Hezbollah’s vulnerability as its communication network was compromised to deadly effect.

How did the pagers explode? The New York Times reported Tuesday that Israel hid explosives inside a batch of pagers ordered from Taiwanese manufacturer Gold Apollo and destined for Hezbollah. A switch was embedded to detonate them remotely, it added.

What is the purpose of the attacks? At least part of the message to Hezbollah is clear: “We can reach you anywhere, anytime, at the day and moment of our choosing and we can do it at the press of a button,” according to CNN’s Chief Law Enforcement and Intelligence Analyst, John Miller.