NEW YORK (MarketWatch) - The U.S. Coast Guard said Saturday it gave BP 48 hours to come up with a way to hasten plans to increase its oil-capturing capacity at the Deepwater Horizon spill, after BP said it could take up to a month to bring in additional equipment.

A June 11 letter from Adm. James Watson to BP PLC BP, -1.18% told BP that "every effort must be made to speed of the process" of capturing more oil, as crude continues to gush out of the sides of and from vents on a containment cap placed on the well two weeks ago.

"BP must identify in the next 48 hours additional leak containment capacity that could be operationalized and expedited to avoid the continued discharge of oil ... with expanded redundancy," Watson wrote in his letter, which the Coast Guard released on Saturday.

BP said Saturday that it continues to collect crude at a rate of 15,000 barrels a day from its gusher in the Gulf of Mexico, as the worst oil spill in U.S. history moves into its seventh week.

BP still plans to deploy a drilling rig next week to help handle the flow of oil, bringing its siphoning capacity to 28,000 barrels a day.

But BP's plan to bring in additional equipment and increase the collection capacity to 50,000 barrels a day would take about a month, officials said this week.

That timeline was unsatisfactory to the Coast Guard, given the government's higher spill estimate of up to 40,000 barrels a day, before BP cut the riser pipe coming from the well and increased the flow in order to fit the current containment cap on it.

A team of scientists and government officials plans to come out with revised estimates of the amount of oil leaking currently from the containment cap, in coming days.

Results from each of the scientific studies will help establish as accurately as possible the volume of oil released by the well. Their findings will likely play a key role in establishing liability.

Meanwhile, efforts continue to drill a relief well to relieve pressure on the uncontrolled gusher, which began April 20 after the Deepwater Horizon rig exploded and killed 11 workers. The relief well is expected to be completed in August.

BP said Saturday it's collected approximately 104,300 barrels of oil since the containment system was put into place several days ago.

Pressure built around BP this week from Wall Street and the White House, as the company's stock price fell to 16-year lows, and recovered later in the week. .

BP's hefty $10 billion annual dividend came into focus, as well as its ability to handle the mounting clean-up costs of the Gulf of Mexico. See: BP nearing dividend cut.

The public, bombarded with images of BP's leaking oil cap on 24-hour news channels, has been angered into growing talk of a boycott of U.S. service stations carrying the company's brand.

On a Facebook page dedicated to boycotting BP, nearly 600,000 people have clicked on the "like it" feature on the Web site.

Less known, perhaps, is the fact that BP set plans in 2007 to sell all of its 700 company-owned and company-operated convenience stores. In addition, about 13,000 BP gas stations around the country were already owned by independent businesses.

BP sells gasoline to those stations as well as a variety of other retailers.

At a press briefing on Friday, Allen said Secretaries Ken Salazar of the Interior Department and Steven Chu of the Energy Department are reviewing BP new containment plan.

The plan includes the placement of a new cap over the leak and building a new riser pipe from the spill to float 300 feet below the surface of the water. The new riser pipe will allow more flexibility for detachment in the event of a hurricane.