LONDON/WASHINGTON (Reuters) - BP Plc promised improved drilling practices on Friday as the company balances twin aims of rebuilding investor and public confidence after the Gulf of Mexico oil spill while not admitting flaws in its own procedures. 
 
 BP said it would more closely oversee the work of its contractors, echoing its position that the rig blast, which killed 11 men and led to the spill, was the fault of its contractors, including driller Transocean and Halliburton. 
 
 The companies have filed lawsuits worth tens of billions of dollars blaming each other for the blast, and any admission by BP that its existing drilling procedures needed improvements could weaken its legal position. 
 
 BP said it would also establish centers for monitoring its drilling wells in real time -- something some rivals already do and which might have prevented the well blow-out that caused the disaster. 
 
 The London-based company declined to comment on whether it was addressing shortcomings in its internal procedures that were highlighted in government investigations, such as its reliance on a single barrier to keep oil and gas in the well. 
 
 BP's rivals including Exxon Mobil, Royal Dutch Shell and BG Group have criticized its design for the Macondo well, saying it contributed to the disaster. 
 
 GOING BEYOND WHAT'S REQUIRED 
 
 BP said its plans go beyond regulatory requirements. 
 
 "BP clearly understands that they have to win back not only the regulators' confidence, but the confidence of the public as well," the head of the U.S. offshore drilling regulator, Michael Bromwich, said at a congressional hearing in Washington. 
 
 The regulator has already established strong, new safety and environmental standards that all operators are required to meet, said Bromwich, director of the Bureau of Ocean Energy Management, Regulation and Enforcement. 
 
 Appointed after the BP spill to overhaul the drilling regulator, Bromwich said he has been pleased by BP's cooperation with the agency since the disaster. He welcomed BP's plans to strengthen safety. 
 
 "We'll always look favorably on companies that will impose on themselves higher safety standards than what our current regulations require," Bromwich said. 
 
 The agency will consider whether to encompass any of the voluntary standards BP has adopted as it moves ahead with plans to develop additional drilling regulations, Bromwich said. 
 
 A BP source told Reuters in April that the company had filed one drilling application. The agency would not offer specific details on Friday about any pending BP applications to drill exploratory wells. 
 
 BP said on Friday that it would only use blow-out preventers (BOPs) -- devices designed to prevent uncontrolled releases of oil and gas from wells -- with twin sets of shears which could slice through drill pipes, and that it would have third parties verify the testing of BOPs. 
 
 The failure of the BOP on the rig that was drilling BP's Macondo well contributed to the oil spill, although the panel convened by President Barack Obama to investigate the disaster said even if it worked properly the fatal blast would still have occurred. 
 
 BP will also require lab testing of the cement mixtures its outside cementing contractors recommend for lining and sealing oil wells, and provide the results to the offshore safety regulator. 
 
 BP's Chief Executive Bob Dudley, who took over from Tony Hayward after the leaking Macondo well was capped, had previously outlined some of the measures at public events in the past month. 
 
 Representative Edward Markey, the top Democrat on the U.S. House Natural Resources committee, said BP's plans show that offshore drillers can comply with tougher safety rules. 
 
 "It is time for the oil industry and their Republican allies in Congress to drop their opposition to stronger requirements," said Markey, an outspoken critic of the oil industry. 
 
 "If BP can do this, so can everyone else," he said. 
 
 (Additional reporting by Malathi Nayak in Washington; Editing by David Hulmes, Jane Merriman and Dale Hudson) ||||| ANCHORAGE/LONDON (Reuters) - BP reported yet another pipeline leak at its Alaskan oilfields, frustrating the oil giant's attempts to rebuild its reputation after the Gulf of Mexico oil spill. 
 
 BP said on Monday that a pipeline at its 30,000 barrel-per-day Lisburne field, which is currently closed for maintenance, ruptured during testing and spilled a mixture of methanol and oily water onto the tundra. 
 
 The London-based company has a long history of oil spills at its Alaskan pipelines, including lines servicing Lisburne. The accidents have hurt BP's public image in the United States, where around 40 percent of its assets are based. 
 
 The Alaska Department of Environmental Conservation said the spill occurred on Saturday and amounted to 2,100 to 4,200 gallons, affecting 4,960 square feet of gravel pad and about 2,040 square feet of wet and aquatic tundra. 
 
 Production from the entire Lisburne field remains shut off while the spill is addressed, Alaska officials said. 
 
 A BP spokesman said the cleanup was under way and the company would determine the cause "in due course." 
 
 Immediate efforts are focused on containment and cleanup, said Tom DeRuyter, state on-scene coordinator for the Department of Environmental Conservation. Cleanup must be completed before the pipe section is excavated, he added. 
 
 "BP has got a goal to have the investigation completed and the line repaired by fall freeze-up," he said. "I do not anticipate the cleanup will take that long." 
 
 The pipeline will also have to be dug up to allow for an investigation into why it failed, DeRuyter said. 
 
 MAINTENANCE WORK 
 
 Lisburne, managed as part of the Greater Prudhoe Bay Unit, has produced no oil since June 18, according to Alaska Oil and Gas Conservation Commission records, suggesting maintenance work requiring a prolonged shutdown. 
 
 Dawn Patience, BP Alaska spokeswoman, said there is not yet an estimated time for the Lisburne field to be back in production. 
 
 "The planned maintenance is ongoing," she said, adding the leak happened when BP was testing recently installed valves in the piping. 
 
 The affected pipeline is an eight-inch diameter line, and the area that leaked runs underground beneath a road, according to the Alaska Department of Environmental Conservation. 
 
 BP's blown out Macondo well caused the worst offshore oil spill in U.S. history, spewing almost 5 million barrels of oil into the Gulf and putting BP's future in the U.S. at risk. 
 
 Previous problems including leaks from corroded pipelines in Alaska and the fatal Texas City refinery blast in 2005 had already earned the company a poor reputation for safety, something analysts say it needs to address if it is to continue to grow in North America. 
 
 In 2009, a crack in a flow line that serves Lisburne spilled around 46,000 gallons of a mixture of oil and water on to the snowy tundra. BP in May agreed to pay a $25 million civil penalty and spend $60 million on enhanced safety measures, to settle a federal probe of a pipeline oil spill on Alaska's North Slope in 2006. 
 
 New York-listed shares in BP were down 0.2 percent, or 9 cents, to $44.20 per share in late afternoon trading. 
 
 (Editing by David Gregorio)
– A burst pipeline in Alaska has prompted BP's latest US spill, with a mixture of methanol, crude oil, and water leaking onto the tundra on Saturday, the company announced. The spill—somewhere between 2,100 and 4,200 gallons—happened during a pressure test and is currently being cleaned up, said a BP rep; the cause of the rupture will be investigated “in due course.” The leaking mixture threatens local vegetation, an Alaska official tells Reuters. “You have actively growing plants and they're very susceptible to the contaminants.” It’s just the latest of many such leaks in Alaska, and comes days after BP pledged safer practices.