It is found in the northern Sinai, Egypt and the Negev.
Egyptian authorities would not confirm numerous news reports that Bedouins from northern Sinai are suspects in last week's bombings.
The northern Sinai is far more economically depressed than the south, which has benefited from tourism-related investments around Red Sea resorts.
The original Israeli plan was for a limited offensive into the northern Sinai.
They subsequently attacked Egyptian artillery in the northern Sinai, convoys, supply trains and troop concentrations.
In northern Sinai, a company established itself along the coastal road between Romani and Baluza on October 6.
Several Palestinians were arrested earlier in the week in the northern Sinai carrying explosives belts.
"We now have more than 500 women from northern Sinai participating."
They also said they had uncovered several caches of explosives and automatic weapons in the desert of the northern Sinai.
El Arish, effectively the capital of the northern Sinai, is about 250 miles northeast of Cairo.