BBC News

US President Barack Obama has called on his party and supporters to back a "new future" of clean energy.

Visiting areas affected by the BP oil spill, he said the full resources of government were being deployed, with 17,500 National Guard troops available.

Mr Obama is touring Mississippi, Alabama and Florida, on his fourth visit to the region since the spill.

Tens of thousands of barrels of oil a day have gushed into the Gulf of Mexico since a rig exploded and sank in April.

Earlier, BP said the cost of cleaning up the oil spillage had risen to $1.6bn (£1bn).

On Monday, the company's share price once again fell sharply, dropping 9% in London and New York.

Directors also met to discuss whether to suspend dividend payments to shareholders, amid pressure from the US government.

BP placed a containment cap on its damaged oil well earlier this month; by last week, it was collecting about 15,000 barrels of oil a day.

It is estimated that some 40,000 barrels of oil a day might have been gushing out before the well was capped.

'Environmental 9/11'

Mr Obama visited the Mississippi town of Gulfport before moving on to Theodore, in Alabama.

"We are confronting the largest environmental disaster in our history, with the largest environmental response and recovery effort in our history," he said there.

In addition, the government had held preliminary conversations with BP about how to deal with compensation claims and expected that a mechanism would be agreed soon, the president said.

He announced measures to protect the Gulf seafood industry, and pledged that beaches in the area could and would be returned to their pristine condition within one or two years.

Continue reading the main story

This week, the BBC is assessing the impact of the Louisiana oil spill. Throughout Tuesday, Caroline Duffield will report from the Niger Delta for the BBC World Service and World News TV.

Full coverage of the oil disaster

Earlier, in a statement aimed both at paid-up Democratic Party members and at millions of individuals who backed his 2008 presidential bid online, the president asked his network to lend their name to a campaign to change the way America produces and consumes its energy.

"Beyond the risks inherent in drilling four miles beneath the surface of the Earth, our dependence on oil means that we will continue to send billions of dollars of our hard-earned wealth to other countries every month - including many in dangerous and unstable regions," he said.

"In other words, our continued dependence on fossil fuels will jeopardise our national security. It will smother our planet. And it will continue to put our economy and our environment at risk.

"We cannot delay any longer, and that is why I am asking for your help."

His remarks followed comments in which he said the ongoing oil spill would change the way the US thinks about energy forever - comparing the effect of the disaster on the environment to the way 9/11 shaped US security policy.

Next steps

While Mr Obama has visited Louisiana a number of times since the start of the crisis, on his latest trip he is touring areas of three other affected states.

He is scheduled to spend the night in the region before returning to Washington on Tuesday.

On Tuesday night the president will make a prime-time TV address to the nation in which he is expected to outline the next steps his administration will take over the spill.

Speaking in Gulfport, Mr Obama said he empathised with those suffering financially from the oil spill, adding that the White House was still gathering facts and stories in order to press BP into awarding adequate compensation.

"There's still a lot of opportunity for visitors to come down here. There are a lot of beaches that have not been affected and will not be affected," the AFP news agency quoted him as saying.

"If people want to help, the best way to help is to come down here and visit."

In a further blow to BP, members of the House of Representatives renewed accusations that the firm's decisions in the run-up to the oil disaster had raised "serious questions".

In a letter to BP chief executive Tony Hayward, the heads of two House committees quoted internal e-mails between BP engineers as saying the site was a "nightmare well".

The letter, signed by Henry Waxman and Bart Stupak, accused BP of "taking shortcuts" on the design and construction of the well in order to finish it.

"In effect, it appears that BP repeatedly chose risky procedures in order to reduce costs and save time and made minimal efforts to contain the added risk," the representatives said.

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