Hezbollah has said it was carrying out a “security and scientific investigation” into the causes of the pager blasts and said Israel would receive “its fair punishment”, Reuters reports.

Diplomatic and security sources speculated that the explosions could have been caused by the devices’ batteries detonating, possibly through overheating. But others said that Israel might have infiltrated the supply chain for Hezbollah’s pagers.

Several experts who spoke with Reuters said they doubted the battery alone would have been enough to cause the blasts.

A reason to doubt the explosions were caused by overheating batteries is that typically only a fully charged battery can catch fire or explode, said Ofodike Ezekoye, a University of Texas at Austin mechanical engineering professor. “It is highly unlikely that everyone whose pager failed had a fully charged battery,” he said.

Israeli intelligence forces have previously placed explosives in personal phones to target enemies, according to the 2018 book Rise and Kill First. Hackers have also demonstrated the ability to inject malicious code into personal devices, causing them to overheat and explode in some instances.

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