WASHINGTON - Tar balls that washed ashore in the Florida Keys were not from a massive oil spill in the Gulf of Mexico, the Coast Guard said Wednesday, but that did little to soothe fears a blown-out well gushing a mile underwater could spread damage along the coast from Louisiana to Florida.

The U.S. and Cuba were holding talks on how to respond to the spill, a U.S. State Department official said, underscoring worries about the oil reaching a strong current that could carry it to the Florida Keys and the pristine white beaches of Cuba's northern coast.

The official was not authorized to comment publicly and spoke to The Associated Press on condition of anonymity.

Oil has been spewing since the offshore drilling rig Deepwater Horizon exploded off the Louisiana coast April 20, killing 11 workers, and sank two days later.

The House Transportation and Infrastructure Committee addressed the spill at a hearing Wednesday where leading Republicans including John Mica of Florida sought to pin blame on President Barack Obama's administration. He cited Interior Secretary Ken Salazar's acknowledgment Tuesday that his agency could have more aggressively monitored the offshore drilling industry.

Outlining what he called the "Obama oil spill timeline," Mica said the administration failed to heed warnings about the need for more regulation and issued "basically a carte blanche recipe for disaster" in approving drilling by the Deepwater Horizon, leased by oil giant BP PLC, and several dozen other wells.

He also said the spill could have been contained more quickly if the Coast Guard and other agencies had a better plan.

"This went on and on," he said. "I'm not going to point fingers at BP, the private industry, when it's government's responsibility to set the standards."

Committee Chairman James Oberstar, D-Minn., took issue with the criticism, saying the drilling was approved early in the Obama administration, essentially continuing practices from President George W. Bush's administration, and that decisions were made by career officials.

"I think it's inflammatory to call it the Obama oil spill, and wrong," Oberstar said.

Government scientists, meanwhile, were surveying the Gulf to determine if the oil had entered a powerful current that could take it to Florida and Cuba and eventually up the East Coast. Questions remained about just how much oil is spilling from the well.

New underwater video released by BP showed oil and gas erupting under pressure in large, dark clouds from its crippled blowout preventer on the ocean floor. The leaks resembled a geyser on land.

BP and the Coast Guard have said about 210,000 gallons of oil a day is gushing from the well, but professors who have watched the video and others say they believe the amount is much higher.

Steve Wereley, a mechanical engineer at Purdue University in Indiana, said he is sticking with his estimate that 3.9 million gallons a day is spewing from two leaks.

His estimate of the amount leaked to date, which he calls conservative and says has a margin of error of plus or minus 20 percent, is 126 million gallons - or more than 11 times the total leaked from the Exxon Valdez disaster in 1989. The official estimate is closer to 6 million gallons.

Another researcher, Timothy Crone of Columbia University's Lamont-Doherty Earth Observatory, said the latest video suggested a leak of at least 840,000 to 4.2 million gallons a day, though poor video quality made it difficult to come up with an accurate figure.

BP has tried several unsuccessful methods to contain the oil, but earlier this week managed to insert a tube into one of the leaks and says it has been sucking about 42,000 gallons a day to the surface.

BP is preparing to shoot a mixture known as drilling mud into the well later this week in a procedure called a "top-kill" that would take several weeks but, if successful, would stop the flow altogether. Two relief wells are also being drilled to pump cement into the well to close it, but that will take months.

Salazar on Tuesday promised an overhaul of federal regulations and said blame rests with both industry and the government, particularly his agency's Minerals Management Service.

"We need to clean up that house," Salazar said of the service.