Oil slick: "the fight to stop the leak is coming to an end," said Obama

More than one hundred days after the start of the spill, Barack Obama said Wednesday that the "fight to stop the leak" of crude coming to an end, after BP announced the successful first phase of patching oil wells in the Gulf of Mexico.

President Barack Obama has described the operation as "very good news," also welcomed an official report that "vast majority" of oil spilled at sea since April "has been dispersed or removed from the water."

"The long struggle to stop the leak and control of oil is near to come to an end. And we're very happy. Our cleaning operations, however, will continue," noted the president.

Optimism shared by Admiral Thad Allen, in charge of the fight against the disaster for the U.S. government.

The administration, said Mr. Allen at the daily briefing at the White House is "very optimistic that there will be no leakage of oil in nature."

The operation "static kill", consisting of injecting sufficient drilling mud to push oil down the shaft and sentence had begun in the Gulf of Mexico on Tuesday at 2000 GMT.

It lasted eight hours, the time needed for the British oil engineers to measure pressure in the well after injection materials and ensure the success of the operation.

"The pressure is now well contained by the hydrostatic pressure of the injected sludge, which was the desired objective of Operation Static kill," the group said.

In all, some 4.9 million barrels (780 million liters) escaped from the well - including 800,000 barrels (127 million liters) were recovered - threatening the rich ecosystem of the five coastal states in the Gulf of Mexico and threatening the local economy.

This operation will also end a nightmare of over three months for the giant British oil spill who has already cost several billion dollars and has seen his reputation tarnished after the failures of several attempts to clogging.

Just the next step, the cementing of wells, for which the U.S. administration has given the green light to BP on Wednesday.

"Given the success of the operation + + static kill and tests positive, I allowed BP to cement the well damaged," said Thad Allen said in a statement.

BP immediately announced that his engineers should begin as early as Thursday to inject the cement that will act as a final cap.

But Mr. Allen, said that BP will still be required to perform the operation "bottom-kill" scheduled for mid-August. The method is to put into service two relief wells to cement permanently the well from below.

Approximately three quarters of the crude that spilled into the Gulf of Mexico have already been eliminated, "said Carol Browner, a White House official on issues of energy and environment.

"Scientists tell us that about 25% (oil) has not been recovered, has not evaporated or was not supported by Mother Nature," she said on ABC.

Despite hoping to finally turn the page of the disaster, the Americans and the administration remained concerned about its long-term ecological consequences.

Jane Lubchenco, the director of the U.S. Agency Oceanic and Atmospheric Administration (NOAA), said to remain concerned "about the impact of long-term" oil spill on the ecosystem that could be felt "for years and may be decades. "

According to a survey by the National Center for Disaster Preparedness (NDCP) with 1,200 inhabitants of affected areas, 40% of them say they have been directly affected, 20% related economic consequences.