A preliminary investigation has found hundreds of pagers that exploded across Lebanon, killing at least 12 people and wounding up to 2,800, had been booby-trapped, a security official said on Wednesday, September 18.

Lebanon opened a probe into the explosions on Tuesday, a judicial official said, adding security services were working to determine the cause of the blasts which have been blamed on Israel.

On Wednesday, a new wave of exploding hand-held devices, this time walkie-talkies, killed nine people and wounded more than 300 across Lebanon, the health ministry said.

"Data indicates the devices were pre-programmed to detonate and contained explosive materials planted next to the battery," the official said about Tuesday's blasts, requesting anonymity to discuss sensitive matters. Some of the devices that exploded were being inspected, the security official said, but "most of them were destroyed and burned".

The official said it was unlikely the lithium batteries inside the devices had heated up and exploded. "Exploding lithium batteries cause a fire-like incident... that may cause minor burns, but the blast from these devices resulted from highly explosive materials," he told AFP.