Government officials said late Wednesday night that oil might be leaking in the Gulf of Mexico at a rate five times larger than initial estimates have suggested. In a hastily called news conference, Rear Admiral Mary E. Landry of the Coast Guard said a scientist from the National Oceanic and Atmospheric Administration had concluded that oil is leaking from a well in the gulf at the rate of 5,000 barrels a day, not 1,000 as had been estimated. While emphasizing that the estimates are rough given that the leak is at 5,000 feet below the surface, Landry said the new estimate came from observations made in flights over the spill, studying the trajectory of the spill and other variables. Doug Suttles, chief operating officer for exploration and production for BP, said that a new leak had been discovered as well. Officials had previously spoken of two leaks in the riser, the 5,000-foot-long pipe that connected the rig to the wellhead and is now detached and snaking along the sea floor. One of those leaks was at the end of the riser and the other at a kink closer to its source, the wellhead. But Suttles said a third leak had been discovered Wednesday afternoon even closer to the source. 'I'm very, very confident this leak is new,' he said. He also said the discovery of the new leak did not lead them to believe that the total flow from the well was different than it was before the leak was found. The new, far larger estimate of the leakage rate, he said, was within a range of estimates given the inexact science of determining the rate of a leak so far below the ocean's surface. 'The leaks on the sea floor are being visually gauged from the video feed' from the remote vehicles, said Doug Helton, a fisheries biologist who coordinates oil spill responses for the National Oceanic and Atmospheric Administration, in an e-mail message Wednesday night. 'That takes a practiced eye. Like being able to look at a garden hose and judge how many gallons a minute are being discharged. The surface approach is to measure the area of the slick, the percent cover, and then estimate the thickness based on some rough color codes.' Landry said President Barack Obama had been notified. 