Hezbollah’s cheap fibre-optic drones are creating new challenges for Israeli troops in southern Lebanon, forcing the military to adapt its tactics against an increasingly lethal threat.

The Israeli military – considered one of the most advanced in the world – has confirmed two soldiers and one civilian contractor killed in explosive drone attacks in under a week, with several others wounded despite a ceasefire in place since mid-April.

The devices are small, cheap and readily available, like...