The US government has given BP 72 hours to present its latest plans to clean up the oil spill in the Gulf of Mexico.
BP says its containment effort is going well, but there are signs of mistrust between the company and the government.
The US justice department is mulling legal action to make sure BP has enough funds to cover the damage and compensate those affected by the slick.
That could mean shareholders are not paid dividends, which would infuriate investors and hit pension funds.
Amid growing public anger in the US, President Barack Obama will make his fourth visit to the region on Monday.
The Obama administration is applying steadily more pressure on the BP, which claims it will have almost completely contained the ruptured oil well by the early part of next week.
Coast Guard Admiral Thad Allen, the man in charge of the clean up operation, has given the company three days to present its latest plans for cleaning up the Gulf.
He also wrote to BP on Tuesday demanding "more detail and openness" about how the company was managing claims for compensation payments to individuals and businesses in the region.
Meanwhile, 33 US House lawmakers sent a letter to BP chief executive Tony Hayward, urging the company not to spend money on a dividend and an advertising campaign to improve BP's image.
"We urge you to halt your planned dividend payout and cancel your advertising campaign until you have done the hard work of capping the well, cleaning up the Gulf Coast and making whole those whose very livelihoods are threatened by this catastrophe," the letter said.
Oil has been leaking into the Gulf of Mexico since the Deepwater Horizon rig exploded and sank off the coast of the US state of Louisiana, killing 11 workers.
Some beaches in Florida are for the first time displaying warning signs telling holiday makers not to swim in the sea here, the BBC's Andy Gallacher reports from the Florida panhandle.
A containment cap placed on the blown-out well last week is now helping to contain some of the leaking oil.
Adm Allen said in a press conference on Wednesday that the operation was catching up to 630,000 gallons (2,800,000 litres) daily.
BP's chief executiveis due to appear before Congress for the first time next week.
The British energy firm's shares fell 3.4% on Wednesday over worries that the company will have to suspend its dividend payments because of the disaster.
Meanwhile, tests have shown that underwater oil plumes have travelled at least 64km (40 miles) from the leaking well, the US government says.