“I’m hopeful that the reforms that the secretary and the administration are undertaking will resolve the flaws in the current system that I inherited,” she said in a statement.
Mr. Obama plans on Friday to inspect the efforts in Louisiana to stop the leak and clean up after it, his second trip to the region since the explosion of the Deepwater Horizon rig on April 20. He will also visit with people affected by the spreading slick that has washed ashore over scores of miles of beaches and wetlands.
Even as Mr. Obama acknowledged that his efforts to improve regulation of offshore drilling had fallen short, he said that oil and gas from beneath the gulf, now about 30 percent of total domestic production, would be a part of the nation’s energy supply for years to come.
“It has to be part of an overall energy strategy,” Mr. Obama said. “I mean, we’re still years off and some technological breakthroughs away from being able to operate on purely a clean-energy grid. During that time, we’re going to be using oil. And to the extent that we’re using oil, it makes sense for us to develop our oil and natural gas resources here in the United States and not simply rely on imports.”
In the top kill maneuver, a 30,000-horsepower engine aboard a ship injected heavy drill liquids through two narrow flow lines into the stack of pipes and other equipment above the well to push the escaping oil and gas back down below the sea floor.
As hour after hour passed after the top kill began early Wednesday afternoon, technicians along with millions of television and Internet viewers watched live video images showing that the dark oil escaping into the gulf waters was giving way to a mud-colored plume.
That seemed to be an indication that the heavy liquids known as “drilling mud” were filling the chambers of the blowout preventer, replacing the escaping oil.
A US  official said today that BP's latest effort to plug the Gulf of Mexico oil spill has been successful in slowing the amount of oil leaking from the well.

The official, Admiral Thad Allen, said that the procedure, known as a "top kill" operation, has been able to block some of the leaking oil at the source, the top of the damaged well.  The operation involves pumping material into the well to plug the leak before cement is used to permanently seal the leak.  Allen said the operation has "been able to force mud down and not allow any hydrocarbons to come up."

BP hasn't confirmed the success of the top kill operation, saying only that the "operation is proceeding as we planned it," and that there had been no major incidents thus far.  Although the possibility of failure is still present, experts say that the longer the procedure continues, the less likely it will be that anything goes wrong.

The procedure began yesterday afternoon, after diagnostics on the damaged equipment on the ocean's surface indicated that it could withstand the added pressure of the mud being pumped into the well.  Although engineers involved with the operation wore concerned that the pressure of the mud might not be able to overcome that of the oil, that has thus far not been the case.

Separately, a group of US scientists announced new estimates of how much oil was flowing from the well, ranging from 12,000 to 25,000 barrels a day, far higher than BP's original estimate of 5,000 barrels a day, a figure which BP warned was possibly inaccurate.

In a press conference Thursday afternoon, US president Barack Obama also announced new measures in response to the spill, which include:
*Suspending off-shore test drilling for six months
*Extending the moratorium on issuing drilling permits for an additional six months
*Cancelling the sale of leases for off-shore drilling.
In statements, Obama criticized the "scandalously close relationship" between government officials and oil companies in the past, saying that the Mineral Management Service, which is the agency responsible for monitoring off-shore drilling, had been corrupt for years.