In a statement, BP said it was ramping up preparations for a "major protection and cleaning effort" on the shorelines of Louisiana, Mississippi, Alabama and Florida.

The statement came as reports suggested that the oil slick had already reached the coast of Louisiana.

The US Coast Guard has sent investigators to confirm whether crude had begun to wash up on parts of the Louisiana shoreline, the BBC reported Friday.

The oil spill, now estimated at 5,000 b/d, began April 20 with explosion of Transocean's Deepwater Horizon semisubmersible drilling rig at the Macondo site. Eleven of the 126 workers from the rig remain missing and presumed dead.

BP said that supplementing its Houma, Louisiana incident command post, which oversees the offshore containment effort and onshore response in Louisiana, it was now establishing a similar command post at Mobile, Alabama, to oversee the onshore response in Mississippi, Alabama and Florida.

Work will also continue to complete installing marine protection booms along the coast, BP said.

"As well as 180,000 feet of boom already in the water, an additional 300,000 feet is staged or in the process of being deployed, with more on the way," it said.

"We are doing absolutely everything in our power to eliminate the source of the leak and contain the environmental impact of the spill," BP CEO Tony Hayward said.

"We are determined to fight this spill on all fronts, in the deep waters of the Gulf, in the shallow waters and, should it be necessary, on the shore," he said.

WEATHER, CURRENT PATTERNS TO SHIFT

BP said the massive offshore operation that has been running for a week has been addressing the spill on the surface offshore, both by skimming and collecting oil and by applying dispersants.

"There is concern, however, that weather and current patterns will shift and move the sheen closer to shore or onshore in the coming days," it said.

The new onshore activity is focused on five locations in the potentially affected states: Venice, Louisiana; Pascagoula and Biloxi, Mississippi; Mobile, Alabama; and Pensacola, Florida.

Staging posts are in place, stocked with people and material, including about 100,000 feet of boom, to protect the shoreline in each area.

"Each of the states has oil spill response plans already in place and trained community groups and volunteers will also be available to aid the response to the oil spill and deploy resources," BP said.

Parallel to these, BP said it was setting up offices in each of these communities manned by company staff to provide information on what is happening, what is being done and any developments.

BP said efforts to stem the flow of oil from the well, currently estimated at up to 5,000 b/d, are continuing with six remotely operated vehicles continuing to attempt to activate the blowout preventer on the seabed.

By the weekend, the Transocean Development Driller III is scheduled to spud a relief well intended to secure the existing well. Drilling of this well is expected to take two to three months, BP said.

"Work is also continuing to produce a subsea collection system capable of operating in deep water to funnel leaking oil to the surface for treatment. This is expected to be ready for deployment in the next few weeks," it said.

"Preliminary estimates indicate that current efforts to contain the spill and secure the well are costing the Mississippi Canyon 252 block owners about $6 million/day. This figure is expected to rise as activity increases. It is too early to quantify other potential costs and liabilities associated with the incident."

--Stuart Elliott, stuart_elliott@platts.com