Two beeps and a pause was the only warning Yusuf got. He turned around to face the noise, thinking it was one of his medical instruments, but instead was met with an explosion, throwing shrapnel into his leg. His patient fared much worse.

“The patient lost consciousness; he started bleeding. His face, neck and lips were burned. He had knife-like cuts, as if he was hit by a rocket,” Yusuf, a doctor from Beirut speaking under a pseudonym, said while waiting for an injured friend outside a Beirut hospital. He rolled up his trouser leg to show a small wound, the remnants of his patient’s exploded pager.

The complex operation – probably carried out by Israeli intelligence – on Tuesday that targeted the pagers used by members of Hezbollah left at least 2,800 injured and 12 dead, including two children and a healthcare worker. A further round of explosions on Wednesday, apparently targeting the group’s walkie-talkie radios, injured dozens more.

The scale of the pager attack was “far greater” than that of the Beirut port blast some four years earlier, the largest non-nuclear explosion in human history, which left more than 7,000 injured, Lebanon’s health minister, Firas Abiad, said on Wednesday.