Hundreds of tunnels under the border between the Gaza Strip and Egypt are keeping many of the Palestinian territory's one and a half million impoverished residents supplied with food and fuel.
On Saturday, Egyptian authorities found the entrances of three tunnels and confiscated a large amount of fuel about to be smuggled into the territory.
Sources say there are more than 6,000 Palestinians employed in the clandestine industry, which merchants say is heavily controlled by the Hamas authorities.
Strict rules are imposed on what can be brought into the territory - weapons, drugs and people trafficking are prohibited - and tunnel operators are taxed. Al Jazeera