(CNN) -- BP's CEO said Sunday he's sorry for the largest oil spill in U.S. history and the "massive disruption" it has caused the Gulf Coast, telling reporters the company hopes to corral most of the crude offshore.

"The first thing to say is I'm sorry," Tony Hayward said when asked what he would tell people in Louisiana, where heavy oil has already reached parts of the state's southeastern marshes.

"We're sorry for the massive disruption it's caused their lives. There's no one who wants this over more than I do. I would like my life back."

Hayward said the company is doing "everything we can to contain the oil offshore," but, "as far as I'm concerned, a cup of oil on the beach is a failure."

Full coverage of oil spill

He said the company now has about 30 aircraft searching for signs of oil and has moved more than 300 people of offshore "floatels" to speed up its response time.

"What we're not faced with is a complete line of oil coming at us. It's more like guerilla insurgency, if I can use military jargon," he said. "And what we need to do is have a rapid response capability to get it as we identify it, rather than have it come onto the shore or onto the marsh."

In other developments late Sunday, a fisherman who was hospitalized after becoming ill while cleaning up oil in the Gulf has filed a temporary restraining order in federal court, asking BP to give the workers masks and not harass workers who publicly voice their health concerns.

Watch: Are oil booms working?

BP said it will strengthen its efforts to stop the flow of oil and protect the coastline after the most recent attempt to stop the Gulf oil spill failed.

"We're disappointed the oil is going to flow for a while and we're going to redouble our efforts to keep it off the beaches," BP Managing Director Robert Dudley said on CNN's "State of the Union."

The most recent setback was the failure of the so-called "top kill" method of pumping mud to plug the leak.

"There was just too much flow," Dudley said.

Dudley gave some details about the new option: A custom-built cap will be fitted over a piece of equipment called the "lower marine riser package."

The process will involve a clean cut of the lower marine riser package, where a cap will then be lowered.

The company will circulate warm water around the area to prevent the freezing that hindered a previous dome-cap effort, Dudley said.

BP does not expect to see a large increase, if any, in the volume of oil from cutting the equipment to create a clean surface to cap, he said, though the result will not be a pressure-tight seal.

The long-term solution is the drilling of a relief well that will be in place by August.

BP reported well control problems in March, e-mails show

"If we can contain the flow of the well between now and August and keep it out of the ocean, that's also a good outcome," Dudley said. "And then, if we can shut it off completely with a relief well, that's not a bad outcome compared to where we are today."

On Sunday, the Obama administration questioned BP's oil spill numbers.

On NBC's "Meet the Press," Carol Browner, Obama's assistant on energy and climate change, said BP may have had an ulterior motive for underestimating the amount of oil leaking.

Read more about numbers dispute

"BP has a financial interest in these numbers. They will pay a penalty based on the number of barrels per day," she said.

BP had originally said about 5,000 barrels of oil per day were leaking. The latest estimate, Browner said, is between 12,000 and 19,000 barrels per day.

"This is probably the biggest environmental disaster we've ever faced in this country," she said.

More oil is leaking into the Gulf of Mexico than any other time in U.S. history, including the 1989 Exxon Valdez oil spill.

A lot of systems are in place to manage and decrease the amount of oil coming on shore, Browner said.

Controlled burns of oil effective so far, though they have been limited because of weather conditions, she said.

As a consequence of the Gulf of Mexico oil spill, all deepwater operations in the Gulf have been shut down for now, including operating wells, Browner said.

"At the end of the day we will make the right decisions ensuring that our environment is protected," she said.

Rescuers plan to release a group of birds Sunday that workers washed and rehabilitated after finding them covered with crude, officials said. A northern gannet and brown pelicans rescued in Louisiana will be transported to a refuge at the mouth of Tampa Bay, Florida, and released Sunday, a statement from the oil spill cleanup command said.

Watch: Marine animals in danger

But officials say more wildlife are at risk as up to 19,000 barrels (798,000 gallons) of oil daily continue gushing from an underwater well that engineers have been unable to cap for more than a month.

Top BP executives said Saturday that engineers and scientists had decided to try a new technique of stopping the flow after three attempts to pump mud and 16 tries to stuff solid material into the well failed.

That option: placing a custom-built cap to fit over the "lower marine riser package," BP chief operation officer Doug Suttles said. BP crews were already at work Saturday to ready the materials for that method, he said.

"We have not been able to stop the flow," a somber Suttles told reporters. "Repeated pumping, we don't believe, will achieve success, so we will move on to the next option."

iReport: Track the oil spill

Suttles and other officials said that the "top kill" attempt to stop the flow did so -- but only as long as they were pumping. When the pumping stopped, the oil resumed its escape.

Suttles said the lower marine riser package cap, which will be ready in four to seven days, "should be able to capture most of the oil" that has fed what is now the largest oil spill in U.S. history. But, he cautioned, the new cap will not provide a "tight mechanical seal."

"We're confident the job will work, but obviously we cannot guarantee success at this time," he said.

Coast Guard Rear Adm. Mary Landry said that BP would resume using undersea dispersants for the new attempt to trap the oil.

Landry said officials were disappointed by Saturday's announcement, but noted that the immediate efforts to stop the flow were never intended to be permanent.

"The real solution, the end state, is a relief well," she said.

BP currently is working on two relief wells, but they are not expected to be ready until August, Suttles said.

Earlier, Suttles said that BP engineers would try to place a second blowout preventer -- the piece of equipment that failed when the Deepwater Horizon exploded on April 20 -- should the lower marine riser package fail. The failed blowout preventer is a 48-foot-tall, 450-ton apparatus that sits atop the well 5,000 feet underwater.

Suttles and Landry praised the clean-up efforts, however, in light of the failure of the "top kill" attempt to stop the flow.

"It's a tribute to everybody that we only have 107 miles of shoreline oiled and only 32 acres of marsh," Landry said.

Plaquemines Parish President Billy Nungesser told CNN Saturday night that BP needed to "step up to the plate tonight to save our wetlands" by using its might to create sand barriers to prevent the oil from moving into the marshes.

The silent environmental crisis

"BP needs to say it will pay to move those dredges and pump that sand berm," he said. "We are gonna die a slow death if we don't get that berm. We've got to have that barrier island."

Sen. Mary Landrieu, a Democrat from Louisiana, echoed the call to bolster barrier islands in a statement Saturday night.

She said BP should immediately invest $1 billion to protect marshes, wetlands and estuaries -- giving half the money to short-term projects protecting the Louisiana coast and half to other Gulf Coast states "based on the immediate threat posed by oil spewing from the well."

President Obama, who toured the area Friday, said federal officials were prepared to authorize moving forward with "a portion of" an idea proposed by local officials, who want the Army Corps of Engineers to build a "sand boom" offshore to keep the water from getting into the fragile marshlands.

But Nungesser said the marshes couldn't wait and that the effort needed to start immediately to save the Louisiana wetlands.

A team of oil spill experts were on standby in the United Arab Emirates, ready to help in the Gulf of Mexico cleanup efforts if called to do so, officials in the Middle Eastern country told CNN Sunday.

Read more about possible help from Mideast

The United Arab Emirates originally made the offer two weeks ago. "Basically, it's an offer made on behalf of the government in recognition of this environmental issue. It is an offer of support," said Craig Buckingham of the Abu Dhabi National Oil Company.



CNN's Jennifer Bixler contributed to this report .