Violence in Saudi Arabia shows up the cracks in the kingdom's security apparatus, John R Bradley reports So far this month, Western individuals working in Riyadh have been specifically targeted four times. Nevertheless, the Saudi authorities have remained powerless to halt a wave of attacks which has seen three Westerners killed in a single week and a United States' national kidnapped in the capital. Complicating the problem facing the Saudi authorities is evidence that Al- Qaeda has now infiltrated Saudi security forces up to the very highest levels, including those entrusted with the protection of expatriate compounds. While security forces are tracking militants across the kingdom, they have failed to arrest three of the four men accused of Al-Khobr killings which took place at the end of May. Six prominent Saudi religious figures this week strongly condemned attacks against non-Muslims. Islam "protects" expatriates living on Muslim soil, the ulema said in a statement carried by the official Saudi Press Agency. "Any aggression" against "any Muslim or non-Muslim" is prohibited by the Quran, the statement said. If the tens of thousands of Western expatriates who find themselves directly in Al-Qaeda's sights decided to leave Saudi Arabia altogether in light of an upsurge in terror attacks against them, their departure would have a devastating impact on the kingdom's key economic sectors. That is what the militants hope to achieve, as they notch up a gear their campaign to overthrow the ruling family. Security failures in Saudi Arabia were picked up in Washington this week, where strong comments were aired suggesting for the first time that a dramatic upsurge in anti-Western violence in the kingdom could endanger the Saudi regime's survival. "The Saudis know that this is an enemy that is coming after them. The killing of foreigners, whether they're Americans or Brits, or whatever they are, is a direct attack against the Saudi regime," said US Secretary of State Colin Powell. "The Saudis now know that they have a very serious problem within the kingdom, and they know that it's going to require all their resources, not only their military and police resources," he added. Comments from senators were even more frank. "I think it's a very dangerous situation for Saudi Arabia. I'm not sure they're equipped to handle it," said Senator John Rockefeller of West Virginia, the top Democrat on the Senate intelligence committee. "I don't think psychologically over their 70-year history they've been equipped to handle this kind of attack. So I worry a lot about their future." Travel agencies in the Eastern Province -- scene of the hostage drama on 29 May in Khobar, in which 22 people were killed -- say big joint ventures and multinational companies have made mass bookings for their American and European executives in recent weeks. There are even unconfirmed reports in the Saudi state media of mass resignations in the state-owned energy giant Saudi Aramco, where Americans make up the bulk of the more than 10,000 Western employees whose expertise the kingdom still largely relies on to run its most vital economic sector. US and Saudi authorities are meanwhile racing against the clock to track the whereabouts of kidnapped American Paul Johnson. Their search is haunted by the gruesome videotape showing the beheading of American civil contractor Nicholas Berg, kidnapped in Iraq in April. Meanwhile, Islamic militants claimed responsibility for gunning down an American and abducting another in the latest of a string of well- planned attacks that singled out Westerners and other non-Muslims who work in the oil and arms industries in Saudi Arabia. A field engineer working on a sophisticated targeting system designed for attacks on helicopters, Johnson was kidnapped by an Al-Qaeda gang that claims to have killed Kenneth Scroggs, a worker for Saudi-based Advanced Electronics Co. The gang said in a message posted on a Web site that it was seeking to "avenge US mistreatment" of Muslim detainees, and would treat Johnson just as "the Americans dealt with our brothers in Guantanamo and Abu Ghraib". The Jeddah-based Okaz newspaper reported that a syringe had been found at the kidnapping site, suggesting that Johnson had been drugged. In response to the security forces' failures, many Western firms in the kingdom are taking security into their own hands. Private security firms have reported a surge in demand for armed guards -- mainly from Western firms -- after the attack in Khobar. This notwithstanding, Powell's remarks that "there is more they [the Saudis] can do" to protect Westerners was echoed by Western expatriates inside the kingdom. "In our apartment accommodation there's no security," said Fergus McArdle from Northern Ireland, who works at Jubail Industrial College, a short drive from Khobar. "Considering what happened in Khobar, it's pathetic. You're safe here, they tell us, and that's what those who were killed in Khobar thought," he told Al- Ahram Weekly. Al-Qaeda cells appear to be holding off from a direct attack on an oil installation or the Saudi royal family, and are instead singling out Western expatriates in a low- level campaign of psychological warfare. Self-proclaimed Al-Qaeda spokesmen say on Web sites that the monarchy's "separate fingers will become an iron fist" if its rule is threatened. A major attack would result in the imposition of a state of emergency, making the movement of "terrorists" much more difficult. Until now, only one suspect has been arrested.