Obama said he shared the "anger and frustration" felt by many Americans, and he acknowledged differing estimates about just how disastrous the damage from the leak could become. He said the administration's response has "always been geared toward the possibility of a catastrophic event."
As Obama spoke in the White House Rose Garden, undersea robots in the Gulf tried to thread a small tube into the jagged pipe that is spewing oil into the water. The blown-out well has pumped out more than 4 million gallons of crude.
BP engineers were trying to move the 6-inch tube into the leaking 21-inch pipe, known as a riser. The smaller tube was to be surrounded by a stopper to keep oil from leaking into the sea. BP said it hoped to know by Friday evening if the tube succeeded in taking the oil to a tanker at the surface.
The Gulf spill is not only a potential environmental and economic catastrophe. It also is a major political challenge for Obama to demonstrate that his administration is doing everything it can to deal with the disaster. An AP-GfK poll this week found that to this point the spill hasn't stained Obama nor dimmed the public's desire for offshore energy drilling. Although some conservative pundits have called this "Obama's Katrina," that's not how the public feels.
Obama slammed BP and other companies responsible for equipment involved in the spill for pointing fingers at each other instead of accepting responsibility.
But he said responsibility rests with the federal government, too, and that oil drilling permits had been granted without appropriate environmental reviews.
"That cannot and will not happen anymore," Obama said. He announced a new examination of the environmental reviews that must happen before oil and gas development goes forward.
With millions of gallons of oil fouling the fragile Gulf ecosystem after a drilling rig exploded April 20 and later sank, Obama said: "It's pretty clear that the system failed and it failed badly." Eleven workers were killed in the accident.
"There is enough responsibility to go around, and all parties should be willing to accept it," the president said.
He said he would not be satisfied until the leak was stopped, the spill was cleaned up and all claims were paid.
This week executives from three oil companies - BP PLC, which was drilling the well, Transocean, which owned the rig, and Halliburton, which was doing cement work to cap the well - testified on Capitol Hill, each trying to blame the other for what may have caused the disaster. Obama decried that scene.
"I did not appreciate what I considered to be a ridiculous spectacle during the congressional hearings into this matter. You had executives of BP and Transocean and Halliburton falling over each other to point the finger of blame at somebody else," the president said.
"The American people could not have been impressed with that display, and I certainly wasn't."
Not long before the spill the president had announced plans for a limited expansion of offshore oil drilling. After the catastrophe, he said those plans would be put on hold pending a 30-day review by Interior Secretary Ken Salazar of safety procedures on oil rigs and at wells.
On Friday the president announced there would be more stringent environmental reviews, too.
The Interior Department said those will focus on whether the Minerals Management Service is following all environmental laws before issuing permits for offshore oil and gas development.
"For too long, for a decade or more, there has been a cozy relationship between the oil companies and the federal agency that permits them to drill. It seems as if permits were too often issued based on little more than assurances of safety from the oil companies," Obama said.
Echoing President Ronald Reagan's comment on nuclear arms agreements with Moscow, he said, "To borrow an old phrase, we will trust but we will verify."
Still, Obama didn't back down from his support for domestic oil drilling, saying it "continues to be one part of an overall energy strategy."
"But it's absolutely essential that, going forward, we put in place every necessary safeguard and protection so that a tragedy like this oil spill does not happen again," he said.