A battalion of Israeli troops withdrew from Gaza after a two day raid to locate and destroy tunnels used to smuggle weapons from Egypt to Gaza. It's not known if the tunnels were discovered by new technical means (ground penetrating radar) or from informers. Naturally, the Israeli aren't talking. At least eight Palestinians were killed (and nearly 40 wounded) fighting the Israeli troops.  Israel say they found and destroyed 70 tunnels in the past three years, and 30 have been found so far this year. The tunnels are dug 40-50 feet beneath the ground and are usually about 400 meters long. Weapons are pulled through the tunnel on a sled. Land owners are paid up to a thousand dollars a month to allow a tunnel to be dug and used from their land. Israelis destroy homes they find a tunnel in.