An 18-year-old Palestinian worker was killed on Monday when a smuggling tunnel beneath Gaza's southern border with Egypt caved in, medical sources said.

Hundreds of tunnels are located beneath the borderline, which were used for bringing in materials forbidden by Israel through the commercial crossing points with Gaza.

Tunnel business flourished between 2007 and the middle of 2010, when an Israeli blockade against Gaza was in its highest level. Construction materials and petrol flow to Gaza mainly through the tunnels.

More than 150 Palestinians were killed in accidents in the tunnels since 2007.