BP has resumed pumping mud into the leaking oil well in the Gulf¹ of Mexico after briefly² suspending the high-risk "top kill" procedure.

英国石油公司采用高风险的“顶部压井”法封锁墨西哥湾泄露原油，在短暂的暂停观测之后，该公司则继续向油井抽送泥浆。

offshore³ drilling unit (right) is pumping the mud" width="226" height="170" src="/upimg/100528/4_061818_1.jpg" />
The Q4000 mobile offshore drilling unit (right) is pumping the mud

The oil giant said it was too early to say whether the latest attempt to stem the leak had been successful.

It has emerged that far more oil has poured from the well than was previously⁴ thought, which would make this the biggest spill（溢出，溅出） in US history.

US President Barack Obama is to visit the affected⁵ area in Louisiana.

Mr Obama has defended his government's handling of the huge oil spill. Speaking at the White House, the president vowed⁶ to hold BP accountable for the "horrific disaster".

He unveiled a series of measures, including a continued moratorium⁷（延期偿付，暂停） on drilling permits for six months.

The move comes after an opinion poll（民意测验） said 60% of Americans were unhappy with the government's response.

Brief suspension

BP suspended its "top kill" procedure, untested at this depth, for several hours on Thursday so it could monitor progress.

It has now resumed pumping heavy mud into the ruptured⁸（破裂的） well.

It says it believes the procedure can work - although it may not know for days yet.

It would take 24-48 hours before BP engineers could tell whether "top kill" had worked, company officials said at about 2000 GMT on Thursday.

If the procedure succeeds, cement（水泥，粘合剂） will be injected to seal the well.

New estimates from a panel of US scientists said at least 12,000 barrels (504,000 gallons) were leaking into the Gulf every day, far exceeding the 1989 Exxon Valdez disaster.

The leak was caused by an explosion on the Deepwater Horizon rig on 20 April, which also killed 11 workers.

President Obama stressed that his administration, and not BP, was in charge.

But he admitted the government did not have the technology to deal with the damaged oil well nearly a mile (1.6km) below the surface, meaning that Washington must rely on BP to plug the ruptured well.