Attack on World’s Largest Refinery Could Cripple Economy. Al Qaeda is planning a new series of terror operations designed to cripple the Saudi monarchy — and the U.S. economy — by attacking Saudi Arabia’s economic lifeline — the oil industry, ABCNEWS has learned. U.S. and Saudi intelligence are particularly concerned about operations by al Qaeda after a previous attack plotted by al Qaeda against Saudi Arabia’s Ras Tanura refinery — the largest in the world — was thwarted last summer. The Persian Gulf complex is vital to the oil industry. The plot was frustrated when the CIA provided intelligence to its Saudi counterparts. The Saudis refused to tell American authorities about their follow-up on the investigation, but Saudi intelligence sources told ABCNEWS that the Saudi government was able to disrupt the operation, arresting five people. Al Qaeda’s repeated attempts against the World Trade Center showed the terror network does not give up on its prized targets. Full Story