Saudi Arabia intends to try to isolate itself from Al Qaeda terrorists based in Iraq by building a “security fence” along the 560-mile border it shares with its troubled neighbor, the London Times reported.

The purpose of the barrier, which would be the longest wall in the world, was reported to be “an attempt to improve internal security and bolster its defenses against external threats.”

The Saudi government have issued specifications for the fence and invited bidders to construct it.

The Saudi rulers believe that the main threat to the stability of their oil rich country is from insurgent Saudi opponents of the oligarchic kingdom who might slip across the open desert border from Iraq.

“There’s no suggestion that the border isn’t secure at the moment, so it could be a bit of an expensive white elephant,” a European diplomat in Riyadh told the London Times. It is thought that the majority of the Saudi-born terrorists responsible for bombings in Saudi Arabia arrive by plane from Damascus, Syria.

The Riyadh regime is said to be concerned that the new Shiite-dominated government in Iraq may become closely allied with the mullahs who run Iran, who have been openly contemptuous of Saudi Arabia’s links with the West.

The Shiites are a minority in Saudi Arabia and mostly live in the country’s eastern province, where the majority of the Saudi oil fields are to be found.