Obama was referring to testimony this week in Congress by officials of the three companies involved in the disaster - BP, Halliburton and Transocean Ltd - none of whom took responsibility for the spill, and instead blamed one another.

"The system failed, and it failed badly," Obama said.

"And for that, there is enough responsibility to go around. And all parties should be willing to accept it."

'No answers'

Almost one month after the explosion on the Deepwater Horizon oil rig that caused the sinking of the platform and subsequent spill, engineers from BP have still not been able to plug the leak.

Jake Sherman, a congressional reporter for the Politico newspaper, told Al Jazeera that it was clear from the hearings in Washington that the oil companies did not have answers to how to tackle the spill.  

in depth

"It was very clear, and it has been said a lot, that they don't how to clean this up. They said that the investigation is still going on and they don't have answers yet," he said.

"One thing they did get out of the oil companies, though, was that BP is willing to pay; it will pay for the clean-up and all forms of legitimate liability."

Visibly angered by that failure to contain the spill and the gravity of the disaster, Obama said he was launching a "top to bottom" review of enforcement of environmental protection safeguards.

"I'm not going to rest or be satisfied until the leak is stopped at the source, the oil in the Gulf is contained and cleaned up, and the people of the Gulf are able to go back to their lives and their livelihoods," he said.

Fisheries and tourism, two of the Gulf Coast's economic mainstays, along with birds, sea turtles and other wildlife, are threatened by the spreading slick.

'Largest response'

In response BP said it was making every effort to stem the leak.

"We are actually applying everything we can," Doug Suttle, the London-based oil firm's chief operating officer, said.

"We have mounted the largest response ever done in the world."

Balls of sticky tar have washed up along stretches of the Gulf coastline [AFP]

Tony Hayward, BP's chief executive, said in a statement: "We absolutely understand and share President Obama's sense of urgency over the length of time this complex task is taking."

But Rick Steiner, a marine conservation biologist from the state of Alaska, cast doubt on BP's ability to significantly reduce the impact of the spill.

"The idea of being able to respond effetively to a large-scale marine spill like this is simple mythology," he told Al Jazeera.

"The state of oil spill clean-up technology has not advanced substantially since the Exxon Valdez [disaster in Alaska in 1989] ... the safety of offshore production and exploration obviosuly has some room for improvement."

Obama's comments came amid growing disagreement over exactly how much oil is being spilled from the damaged well with some experts saying the amount flowing into the sea was much higher than previous estimates.

According to recent estimates based on undersea video of the leak, oil may be spewing from the site at a rate of up to 70,000-100,000 barrels a day, far faster than a government estimate of 5,000 barrels a day.

The leak was caused by an explosion on April 20 aboard the Deepwater Horizon rig which killed 11 oil workers.

The rig, leased by BP from owners Transocean, sank two days later, rupturing the well pipe in several places and allowing oil to gush into the Gulf of Mexico unchecked ever since.

'Insertion tube'

On Friday, engineers using underwater robots struggled to implement their latest tactic to try and contain the leak approximately 1.6km down on the seabed.

The aim is to attach an "insertion tube" to funnel the oil up to a container vessel on the surface, but the process was taking longer than expected.

In video


BP video footage shows gas and crude oil gushing out from a ruptured pipe

"It's really complicated because of the depth," John Crabtree, a BP spokesman, told the AFP news agency.

The tube has been billed as more effective than a previous plan to use a container - dubbed a "top hat" - which engineers had earlier tried to lower over the leak to collect and then siphon away the oil.

If the latest effort fails, officials have said it will take about 90 days to permanently cap the leak by drilling a relief well.

The government has also been criticised over its response to the disaster, with an environmental group on Friday formallly filing notice of intent "to sue interior secretary Ken Salazar for ignoring marine-mammal protection laws".

An environmental group, the Center for Biological Diversity,  said it had formally filed notice of intent "to sue Interior  Secretary Ken Salazar for ignoring marine-mammal protection laws."
  
"Under Salazar's watch, the Department of the Interior has treated the Gulf of Mexico as a sacrifice area where laws are ignored and wildlife protection takes a backseat to oil-company profits," Miyoko Sakashita, the oceans director for the Centre for Biological Diversity, said.