US President Barack Obama has called on his party and supporters to back a "new future" of clean energy.
美国总统奥巴马号召他所在的政党和支持者共同推动清洁能源的“新未来”。
Visiting areas affected by the BP oil spill（漏油，浮油） , 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（涌出，迸出） into the Gulf of Mexico since a rig（钻探设备） exploded and sank in April.
Earlier, BP said the cost of cleaning up the oil spillage（溢出，溢出量） 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（股息，奖金） 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（面对） 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（赔偿要求） 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（原始的，纯朴的） condition within one or two years.
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（固有的，内在的） 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（矿物燃料） will jeopardise（危及） our national security. It will smother（窒息） 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.