Despite an escalating federal response, President Barack Obama has faced growing criticism of his response to the worst oil spill in U.S. history. On Saturday, Mr. Obama, in a statement, said the administration would pursue "any and all responsible means of stopping the leak until the completion of the two relief wells currently being drilled."

U.S. President Barack Obama, left, LaFourche Parish President Charlotte Randolph and Coast Guard Admiral Thad Allen, national incident commander for the spill, take a tour Friday of areas affected by the Gulf Coast oil spill.

"Every day that this leak continues is an assault on the people of the Gulf Coast region, their livelihoods, and the natural bounty that belongs to all of us," he said. "It is as enraging as it is heartbreaking, and we will not relent until this leak is contained, until the waters and shores are cleaned up, and until the people unjustly victimized by this manmade disaster are made whole."

But Mr. Obama's frustration can't change the fact that a new fallback effort to control the leak will be difficult and risky. BP says it plans to try for a second time to contain the oil flowing out of its broken well, 5,000 feet below the surface. The company says it will try to cut a riser pipe and fit a containment structure over the leak.

Mr. Obama said this method is "not without risk and has never been attempted before at this depth," and he said that was why it had not been activated until now. The only sure way to stop the spill, estimated at 12,000 to 19,000 barrels a day, is for BP to drill a relief well more than three miles under the sea floor to divert the flow. That could take another two months.

Until the flow of oil stops, the disaster will consume time, attention and resources that the White House could have deployed to advance other priorities—such as new measures to fight unemployment or climate and energy legislation.

BP's failure could intensify calls for Mr. Obama to take a more aggressive role in controlling the spill.

At least one member of Mr. Obama's party—Sen. Bill Nelson of Florida—has called on Mr. Obama to "completely take over" the spill-containment effort, possibly with the military in charge.

Sen. Lamar Alexander (R, Tenn.) suggested Sunday in an appearance on C-SPAN's "Newsmakers" program that a 1990 law passed in the wake of the Exxon Valdez disaster could be used by Republicans as a way to challenge the president's response.

President Obama, in a press conference Friday, said it was "simply not true" that the federal government was allowing BP to make all the decisions and White House Energy Czar Carol Browner has portrayed the government as assertive in its interactions with BP. She said the government demanded that BP halt its "top kill" procedure after becoming concerned the operation was putting too much pressure on the well, for example.

Mr. Obama has put Energy Secretary Steven Chu, a Nobel prize winning physicist, in charge of a team of scientists working with BP officials on solutions. Mr. Obama's aides have said the technical expertise and resources to stem the leak lies with BP and the oil industry, not the government.

While some industry experts have said the government could hire another oil company with experience in deepwater drilling to take over the operation, administration officials have so far not taken that option.

In the meantime, Mr. Obama is escalating federal efforts to clean up spilled oil offshore and along the Louisiana coastline.

U.S. Interior Secretary Ken Salazar, Environmental Protection Agency Administrator Lisa Jackson and NOAA Administrator Jane Lubchenco will return to the Gulf region next week to inspect coastline protection and cleanup activities and meet with top BP officials and government and independent scientists and engineers who are working with BP to stop the spill, the administration said.

The administration, responding to complaints from local officials in Louisiana, said it would triple the workers assigned to places where oil has hit the shore within 24 hours of landfall.

Mr. Obama last week said the disaster should spur action in the U.S. Congress to enact measures to cut the economy's consumption of oil—part of broader legislation aimed at attacking climate change. But the climate issue is stalled in the Senate, in part because expanding offshore oil exploration was a key provision meant to attract Republican support.

Mr. Obama says he still believes offshore oil exploration is necessary as a bridge to a future when motor vehicles—the main consumers of petroleum—run on alternative fuels. But on Thursday he ordered a six-month moratorium on new offshore drilling, saying he was wrong to believe oil-industry assurances that a disaster such as this couldn't happen.

A spill that continues fouling the Gulf through the summer, threatening Florida beaches and rich Louisiana fisheries, appears more likely to embolden opponents of offshore drilling, some of whom have pledged to filibuster the climate bill unless the provisions on offshore drilling are eliminated.

The spill raises the odds that the U.S. Congress will pass legislation to increase the limits on the legal liability of companies involved with spills. Democrats in Congress are pushing legislation that would raise the liability cap on oil companies involved in spills to at least $10 billion from $75 million currently. Industry officials say such legislation would make oil and natural-gas operations in the Gulf uninsurable for all but the largest companies, and discourage domestic oil exploration.