Russia's prosecutor general on Friday ordered a review of structures built on permafrost after concluding that a major Arctic fuel spill last week was caused by shifting ground. Prosecutors said in a statement they reached a preliminary conclusion that the spill was due to "sagging of the ground and the concrete foundation" which caused the reservoir's failure. The prosecutor "ordered a comprehensive review of such objects" to prevent similar accidents "on especially dangerous structures on territories prone to melting of permafrost." ma/mm/bp