The Obama administration announced Wednesday that it had rescinded its decision to expand offshore oil exploration into the eastern Gulf of Mexico and along the Atlantic Coast because of weaknesses in federal regulation revealed by the BP oil spill. Interior Secretary Ken Salazar said that a moratorium on drilling would be in force in those areas for at least seven years, until stronger safety and environmental standards were in place. The move puts off limits millions of acres of the Outer Continental Shelf that hold potentially billions of barrels of oil and trillions of cubic feet of natural gas. The latest decision is an admission that the plan announced last spring to open vast new coastal areas to oil and gas development was made without heeding the dangers of deepwater drilling and the profound flaws in the government's program for overseeing it. 'As a result of the Deepwater Horizon oil spill, we learned a number of lessons,' Salazar said in an afternoon briefing, 'most importantly that we need to proceed with caution and focus on creating a more stringent regulatory regime.' After the BP spill, Salazar disbanded the discredited agency charged with regulating offshore oil and gas operations, the Minerals Management Service, and replaced it with a new bureau with enhanced powers. Exploration and production will continue in the central and western Gulf of Mexico under new safeguards put in place after the deadly BP Deepwater Horizon explosion and oil spill in April. Future gulf leases will be subject to further environmental and safety studies, he said. Shell's pending lease in the Arctic Ocean off the Alaska coast will be honored, but drilling will be allowed only after a new environmental review is completed and additional spill response requirements are met. That may push the oil company's plans back by a year or more, officials said. Other potential drilling sites in the Arctic will be studied before any leasing decisions are made for the 2012-2017 period, Salazar said. 