The U.S. government has given oil giant BP 48 hours to offer a plan to better contain oil leaking from the damaged well in the Gulf of Mexico.
In a letter sent Friday, U.S. Coast Guard Admiral James Watson instructed BP's Chief Operating officer Doug Suttles to identify additional leak containment capacity.
On Thursday, BP provided the government with a plan to double the amount of oil it is collecting, but it will be mid-July before bigger tanker ships, flexible pipes and a more permanent containment cap can be put in place.
In his letter, Admiral Watson said BP must expend every effort to speed up the process.
Meanwhile, U.S. President Barack Obama and British Prime Minister David Cameron discussed the oil spill during a phone conversation Saturday. The White House says the leaders agreed BP must do all it can to respond effectively to the situation.
President Obama has been highly critical of BP, which is one of Britain's most economically important companies. The White House has denied, however, that the Gulf crisis has caused tension between the two governments.
On Monday, Mr. Obama travels to the Gulf Coast, his fourth trip to the region since the crisis began.
Mr. Obama has also summoned top BP executives for a meeting at the White House on Wednesday, though it is unclear who will attend.
At this point, nearly two months after a drilling rig explosion and equipment failure allowed geysers of oil to begin pouring out of the well, a possible permanent solution is about two months away.
BP has placed a containment cap over the drill shaft at the bottom of the Gulf, and is collecting about 16,000 barrels of oil a day - less than half the current output of the well, as it is estimated by the U.S. Geological Service.
Coast Guard Admiral Thad Allen, chief of the U.S. government team assigned to the crisis, said Friday that BP's goal is to capture 50,000 barrels of oil per day.
The company's plan to permanently stop the oil flow is to drill two new holes in the sea bottom, angled to intercept the well shaft in a thick layer of rock thousands of meters below the surface, at a point where the leak can be plugged with concrete.