An oil well at the site of a drilling platform that exploded and sank is spewing up to 1,000 barrels of oil per day into the Gulf of Mexico, 50 miles from Louisiana's coast, a Coast Guard commander said today. Rear Adm. Mary Landry said the leak was discovered this morning, at a well that had been connected to the destroyed oil rig and previously had been considered secure. She said the well is leaking from the sea bed, 5,000 feet below the gulf's surface. "This is a very serious spill," Landry said at a news conference in Robert, La.

The leak is at the site where the massive oil rig Deepwater Horizon exploded on Tuesday -- requiring the evacuation of 115 workers -- and burned until it sank two days later. Eleven workers are presumed to have died in the disaster. The cause of the explosion is unknown. It was unclear how the leak in the well would be plugged.

"Our response plan is focused on quickly securing the source of the subsurface oil emanating from the well, clean the oil on the surface of the water, and keeping the response well offshore," said Landry.

Before the discovery of the leak, the Coast Guard had said the well was not leaking oil – and cleanup had focused on a "sheen" of petroleum on the water's surface that the Coast Guard said has grown from one mile by eight miles to 20 miles by 20 miles over the past several days. The edge of that sheen is now roughly 40 miles from Louisiana's marshy coastline, the Coast Guard said. But containment and cleanup of that "oily water" mix was suspended today because of high winds, rain and eight- to 10-foot waves, Petty Officer Connie Terrell said. Nearly 34,000 of gallons of the oil-and-water blend have been collected, Terrell said.

The sunken rig was owned by the Swiss firm Transocean Ltd. and leased to British oil company BP PLC, which had been doing exploratory drilling from the platform.