Hundreds of pagers detonated simultaneously across Lebanon on Tuesday as part of what’s believed to be a coordinated attack against members of Hezbollah, killing at least nine people and wounding some 2,750 more.

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Hezbollah has not said why the pagers exploded, but did say it held Israel “fully responsible for this criminal aggression.” Israel has not yet claimed responsibility for the attack, but had signaled, one day prior, that it was considering a heightened military campaign against Hezbollah, which has for months been firing rockets into Israel in support of Hamas.

UN spokesperson Stéphane Dujarric told reporters Tuesday that the developments in Lebanon were “extremely concerning,” adding that there’s now a higher risk of escalation in the Middle East. In particular, the surprising nature of the damage caused has raised concerns that a new front has opened up on warfare: a form of sabotage that transforms innocuous gadgets into deadly devices.

“Hezbollah made an error when they told their top echelon to stop using mobile phones because they feared they could be tracked,” says Alan Woodward, a cybersecurity professor at the University of Surrey. “They decided to switch to pagers, but they were known to only use a small number of vendors.”

It’s believed that the pagers attacked were produced by Taiwanese manufacturer Gold Apollo, based on images of destroyed devices in the immediate aftermath of the attack. There is no suggestion Gold Apollo knew about the alteration of its devices. (Gold Apollo did not immediately respond to Fast Company’s request for comment, made outside working hours in Taiwan.)

The batch of pagers used by Hezbollah representatives is believed to have contained a small explosive charge within the device that was triggered by a simple message sent to the pagers, according to a former British Army munitions expert who spoke to the BBC. And terror groups and governments alike have in the past detonated bombs through text message. “Intelligence and security organizations have a history of being innovative using relatively simple means,” says Woodward. For example, Hamas engineer Yahya Ayyash was killed in 1996 when he answered what turned out to be a duplicate of his personal cell phone, which contained a small bomb.

“Fundamentally, there’s nothing new [with Tuesday’s attack],” says an experienced UN weapons inspector, who spoke to Fast Company on the condition of anonymity. “It was done nearly 30 years ago.”