HAMMOND, La. -- At first, BP tried to stop the oil rushing into the Gulf of Mexico by flipping a blowout preventer switch. A week ago, they attempted to capture the leak with a 100-ton box. Now they've hit a snag as they try to guide a mile-long tube into the gusher to siphon the oil.

Interior Secretary Ken Salazar said BP had a problem Saturday with the latest effort to stop the leak, but was continuing its work at the ocean floor.

"There was a problem. They had to reconfigure. They are back down again ... trying to get it inserted," he told reporters during a briefing Saturday morning, declining to offer further information.

BP PLC has offered scant details of its progress in trying to thread the 6-inch tube into the 21-inch pipe spewing oil from the ocean floor. Company spokesmen said technicians are continuing the methodical work of using joysticks to guide the deep-sea robots that are manipulating the contraption, but wouldn't elaborate on Salazar's report.

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"We've never done such operations before and we need to take our time to get it right," spokesman Jon Pack said in an e-mail Saturday.

The tube is intended to suck oil up like a straw to a tanker on the surface, while a stopper surrounding it would keep crude from leaking into the sea.

The company also received word that federal regulators had approved spraying chemical dispersants beneath the sea, a contentious development because it has never been done underwater.

Traditionally used on the ocean surface, chemical dispersants act like a detergent to break the oil into small globules, which allows it to disperse more quickly into the water or air before currents can wash it ashore. Louisiana officials claim BP and the Environmental Protection Agency ignored their concerns about how the chemicals may harm the sea floor.

More than three weeks after the oil rig explosion that killed 11 workers and set off the disastrous spill, President Barack Obama assailed oil drillers and his own administration Friday as he ordered extra scrutiny of drilling permits. He condemned a "ridiculous spectacle" of oil executives shifting blame in congressional hearings and denounced a "cozy relationship" between the companies and the federal government.

"I will not tolerate more finger-pointing or irresponsibility," Obama said in the White House Rose Garden, flanked by members of his Cabinet.

"The system failed, and it failed badly. And for that, there is enough responsibility to go around. And all parties should be willing to accept it," the president said.

Obama's tone was a marked departure from the deliberate approach and mild chiding that had characterized his response since the rig went up in flames April 20 and sank two days later. At least 210,000 gallons of oil has been leaking into the Gulf each day, and BP has sought to burn the crude off the surface of the water, as well as use the chemical dispersants.