Four Palestinians were killed on Sunday when a tunnel used for smuggling between the Gaza Strip and Egypt collapsed on top of them, medics said.

The victims were between the ages of 17 and 25, they said. The tunnels were thought to have collapsed after torrential downpours that hit the region over the last several days.

Smuggling tunnels have mushroomed along the Gaza-Egypt border since 2006, when Israel turned the screws on the impoverished territory in response to the electoral victory of Hamas in legislative polls.

The tunnels are used to smuggle medicines, food and basic supplies into the territory in light of the Israeli siege. Israel claims that they are also used to smuggle weapons.