Security in Iraq has collapsed so dramatically that Saudi Arabia has ordered the construction of a 550-mile high-tech fence to seal off its troubled northern neighbour.
"Surveillance has already been stepped up over the past 18 months," said Nawaf Obaid, the director of the Saudi National Security Assessment Project, an institute that advises the government on security affairs.
"But the feeling in Saudi is that Iraq is way out of control with no possibility of stability. The urgency now is to get that border sealed: physically sealed."
The fence is a fresh sign that key allies of the United States in the Middle East are resigned to worsening violence and the possible break-up of Iraq, where American intelligence agencies said this week that the continuing conflict fuelled global terrorism. The National Intelligence Estimate, a report compiled by 16 spy agencies, concluded that the Iraq war had become a cause célèbre for Islamic extremists and was cultivating supporters for the global jihadist movement
For Saudi Arabia, whose nationals have been accused of playing a key role as foreign fighters in the Iraq insurgency, the deterioration in its northern neighbour is a security nightmare.
Saudi officials are worried about so-called "blowback", in which Saudi insurgents in Iraq bring jihad back to the streets of Riyadh and Jeddah. But they are mostly concerned that an Iraqi civil war will send a wave of refugees south, unsettling the kingdom's Shia minority in its oil-producing east.
"If and when Iraq fragments there's going to be a lot of people heading south and that is when we have to be prepared," said Mr Obaid.
"Everyone you speak to in Saudi Arabia says it is now desperately urgent," said Anthony Forester-Bennett, from Westminster International, a British company bidding to help build the fence. "They say there's a real danger of very nasty people coming across from Iraq."
