"For too long, for a decade or more, there has been a cosy relationship between the oil companies and the federal agency [the Minerals Management Service, MMS] that permits them to drill," he said in the Rose Garden.
"It seems as if permits were too often issued based on little more than assurances of safety from the oil companies. That cannot and will not happen anymore. To borrow an old phrase, we will trust but we will verify."
Interior Secretary Ken Salazar, Mr Obama added, was working on a "top-to-bottom reform" of the MMS.
It was announced earlier that the MMS department which permits oil and gas drilling and collects royalties would be separated from the MMS department in charge of inspecting the safety of oil rigs and platforms and enforcing the law.
Booms are being used to hold back the slick off Louisiana
Mr Obama said he shared the anger felt by Gulf Coast residents over the spill and the "potential devastation" they faced.
"I know BP has committed to pay for the response effort and we will hold them to their obligation," he added.
Referring to Congressional hearings on the disaster this week, he said: "I did not appreciate what I considered to be a ridiculous spectacle... executives of BP and Transocean and Halliburton [the firm responsible for cementing the well] falling over each other to point the finger of blame at somebody else.
"The American people cannot have been impressed with that display and I certainly wasn't."
Declaring the system had "failed and... failed badly", he said all the parties involved should be willing to accept some responsibility, including the federal government.
This sense of anger at the White House will not be lessened by an interview in which BP chief executive Tony Hayward was quoted by the UK's Guardian newspaper as saying that the Gulf of Mexico was "a very big ocean" and the spill "relatively tiny" in comparison, BBC North America editor Mark Mardell says.
The spill is poised to become the worst environmental disaster in US history.
Some scientists have begun to cast doubt on official estimates of the rate of oil flow, saying the widely repeated figure of 5,000 barrels of oil per day dramatically understates the amount.
Florida State University oceanographer Ian MacDonald has estimated the rate is four or five times the government figure, the New York Times reports.
Other researchers who have analysed underwater video of the leak released by BP told US news media outlets the leak was spewing about 70,000 barrels per day, with a margin of error of plus-or-minus 20%.
Referring to the issue on Friday, President Obama said there was a "level of uncertainty" over the leak's extent "since no one can get down there in person".
Underwater efforts to cap oil leak
Initially, BP tried to lower a 125-tonne, 18-metre (59 feet) high container dome over the main leak on the sea floor. However, this failed when gas leaking from the pipe mixed with water to form hydrates, ice-like crystals, that blocked up the steel canopy.
Instead, engineers have lowered a smaller device onto the site. Dubbed the Top hat, it will sit over the tear in the pipe and partially stop the leak. To prevent the build up of hydrates, methanol is pumped into the top hat to disperse the water and gas.
The top hat is 1.5m (5 feet) high and 1.2m in diameter. Two special side lines are used to pump methanol into the top hat to displace water and gas leaking from the broken oil pipe. This should prevent the build-up of hydrates. Once in place, oil can be pumped up to the surface.
BP plan to lower the original subsea containment dome over the top hat to provide a better seal over the leaking site and pump oil up to the surface. This time, it will be attached to a pipe that can pump warm water into the dome to prevent the build-up of hydrates.
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