From Iraq’s Insurgency Nearly Half Saudi:
About 45% of all foreign militants targeting U.S. troops and Iraqi civilians and security forces are from Saudi Arabia; 15% are from Syria and Lebanon; and 10% are from North Africa, according to official U.S. military figures. Nearly half of the 135 foreigners in U.S. detention facilities in Iraq are Saudis, a senior U.S. officer said. Fighters from Saudi Arabia are thought to have carried out more suicide bombings than those of any other nationality, he said.
The situation has left the U.S. military in the awkward position of battling an enemy whose top source of foreign fighters is a key ally that at best has not been able to prevent its citizens from undertaking attacks in Iraq, and at worst shares complicity in sending extremists to commit attacks.