The White House has hailed the "beginning of the end" of the Gulf of Mexico oil spill crisis.
White House spokesman Robert Gibbs made the announcement after BP claimed "a significant milestone" in sealing its ruptured well for good and US government scientists reported that nearly three-fourths of the spilled crude had been dispersed, captured or had evaporated.
He said: "It is sort of the beginning of the end of the sealing and containment phase of this operation.
"Our commitment to those families, to those communities in and along the Gulf Coast, remains the same. There is still lots of work to do, and this government will be there every step of the way."
Thad Allen, the top government official overseeing the oil spill response, said the job would not be complete until a relief well is finished later this month, but he called the "static kill" operation a "significant step".
US President Barack Obama's approval ratings have been hurt by public discontent over the government's response to the worst oil spill in US history, and he and his top aides have scrambled to recover lost ground.