ROBERT, La. (AP) — BP has failed in its latest attempt to plug the oil leak in the Gulf of Mexico with mud and cement, the company said Saturday.

BP Chief Operating Officer Doug Suttles said the company determined the “top kill” method had failed after studying it for three days. The method involved pumping heavy drilling mud into a crippled well 5,000 feet underwater.

“We have not been able to stop the flow,” Suttles said. “We have made the decision to move onto the next option.”

It was the latest setback for the company trying to stop the crude from further fouling waters, wildlife and marshland. Other attempts included a gigantic box placed over the leak and a tube inserted to siphon the oil away. The box failed after ice-like crystals clogged it, while the tube was removed to make way for the top kill after it sucked up more than 900,000 gallons of oil.

The spill is the worst in U.S. history and has dumped between 18 million and 40 million gallons into the Gulf, according to government estimates.

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BP says it’s already preparing for the next attempt to stop the leak. Under the new plan, BP would use robot submarines to cut off the damaged riser from which the oil is leaking, and then try to cap it with a containment valve. The new attempt would take four days to complete.

“We’re confident the job will work but obviously we can’t guarantee success,” Suttles said of the new plan.

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AP Radio correspondent Shelly Adler and Associated Press writer Ivan Moreno contributed to this report.

Copyright 2010 The Associated Press.