Israeli soldiers keep watch as workers search for tunnels reportedly used by Hamas militants

The Israeli army has started work on an underground wall along the Gaza border to stop Hamas militants from launching attacks through tunnels.

The $600 million project, which will cover the entire 37-mile border, will take years to complete.

The first section is being built along northern Gaza, near a cluster of Israeli villages where cranes and other construction equipment were visible over the weekend.

General Gadi Eizenkot, the Israeli army chief, said it was the largest project ever carried out by the engineering corps.

An above-ground barrier of concrete walls and barbed-wire fences already covers most of the frontier. Dozens of young Palestinians have managed to scramble over the fence this year, many looking for work, but the barrier has largely deterred Hamas from