A BP executive says a relief well is the "end point" of efforts to stop the Gulf oil spill — which suggests there's little chance of plugging the leak until the new well is completed in August.

With BP declaring failure in its latest attempt to plug the uncontrolled gusher feeding the worst oil spill in U.S. history, the company is turning to yet another mix of risky undersea robot maneuvers and longshot odds to keep crude from flowing into the Gulf.

Robert Dudley, BP's managing director, said on "Fox News Sunday" that company officials were disappointed that they "failed to wrestle this beast to the ground." But skepticism is growing that BP can solve the crisis.

Dudley told ABC's "This Week" that the new attempt to cap the leaking well would at best minimize the oil flowing into the Gulf of Mexico.

Dudley says the relief well expected to be ready at the end of August "is certainly the end point on this game."

This next attempt will be similar to a containment dome that failed to work.

BP hopes to saw through a pipe leading out from the well and cap it with a funnel-like device using the same remotely guided undersea robots that have failed in other tries to stop the gusher. None of the remaining options would stop the flow entirely or capture all the crude before it reaches the Gulf's waters.

Engineers will use remotely guided undersea robots to try to lower a cap onto the leak after cutting off part of a busted pipe leading out from the well. 

Dudley says BP will try to pump warm sea water down the pipe to keep the oil and gas warmer and prevent ice from forming. That was blamed for the earlier failure.

Six weeks after the catastrophe began, the oil giant is still casting about for at least a temporary fix to the spewing well underneath the Gulf of Mexico that's fouling beaches, wildlife and marshland.

The relief wells currently being drilled — which are supposed to be a better long-term solution — won't be done for at least two months. That would be in the middle of the Atlantic hurricane season, which begins Tuesday. The crude likely won't affect the formation of storms, but the cyclones could push the oil deeper into coastal marshes and estuaries and turn the oil into a crashing black surf.

BP said Saturday that the procedure known as the "top kill" failed after engineers tried for three days to overwhelm the crippled well with heavy drilling mud and junk 5,000 feet underwater.

Rep. Ed Markey, D-Mass., who leads a congressional committee investigating the disaster, told CBS' "Face the Nation" on Sunday that he had "no confidence whatsoever in BP."

"So I don't think that people should really believe what BP is saying in terms of the likelihood of anything that they're doing is going to turn out as they're predicting," he said.

The spill is the worst in U.S. history — exceeding even the 1989 Exxon Valdez disaster — and has dumped between 18 million and 40 million gallons into the Gulf, according to government estimates. The leak began after the Deepwater Horizon drilling rig exploded in April, killing 11 people.

"This scares everybody, the fact that we can't make this well stop flowing, the fact that we haven't succeeded so far," BP Chief Operating Officer Doug Suttles said Saturday. "Many of the things we're trying have been done on the surface before, but have never been tried at 5,000 feet."

He said cutting off the damaged riser isn't expected to cause the flow rate of leaking oil to increase significantly.

Experts have said that a bend in the damaged riser likely was restricting the flow of oil somewhat, so slicing it off and installing a new containment valve is risky.

"If they can't get that valve on, things will get much worse," said Philip W. Johnson, an engineering professor at the University of Alabama.

In the days after the spill, BP was unable to use robot submarines to close valves on the massive blowout preventer atop the damaged well, then two weeks later, ice-like crystals clogged a 100-ton box the company tried placing over the leak. Earlier this week, engineers removed a mile-long siphon tube after it sucked up a disappointing 900,000 gallons of oil from the gusher.

Word that the top kill had failed hit hard in fishing communities along Louisiana's coast, where the impact has been underscored by oil-coated marshes and wildlife.

The top official in coastal Plaquemines Parish said news of the top kill failure brought tears to his eyes.

"They are going to destroy south Louisiana. We are dying a slow death here," said Billy Nungesser, the parish president. "We don't have time to wait while they try solutions. Hurricane season starts on Tuesday."