The U.S. Coast Guard announced on Saturday it has ordered BP to improve its plan to contain the oil spill in Gulf of Mexico in 48 hours, as the company's efforts are deemed not enough in light of new oil flow estimates.

In a letter to BP dated June 11, the Coast Guard's Rear Admiral James Watson said the company's current plans do not go far enough to contain the devastating spill, and "BP must identify in the next 48 hours additional leak containment capacity that could be operationalized" to avoid continued oil leak.

According to the White House, the oil spill is already the biggest environmental disaster that the country has ever faced, and scientists on Thursday raised the estimate of the amount of crude oil flowing from BP's damaged well in the Gulf of Mexico to between 20,000 barrels to 40,000 daily, drastically higher than the prior estimate of 12,000-19,000 bpd issued on May 27.

Watson said BP's plan to collect oil is consistent with the previous flow rate estimate, but in light of the new estimate and "substantially higher flow of oil ... it is clear that additional capacity is urgently needed."

"I am concerned that your current plans do not provide for maximum mobilization of resources to provide the needed collection capacity consistent with revised flow estimates," Watson said. He also voiced concerns that BP's current plan does not go far enough to mobilize redundant resources "in the event of an equipment failure" or other unforeseen problem.