BP also said on Monday that its partners in the leaking well must share responsibility for the costs in dealing with the disaster.

"Other parties besides BP may be responsible for costs and liabilities arising from the oil spill, and we expect those parties to live up to their obligations," Tony Hayward, BP's chief executive, said in a statement.

It said that the co-owners had confirmed to the US federal government that they would be liable for oil spill cleanup costs.

'Gross negligence'

It follows Anadarko Petroleum Corp., which has a 25 per cent stake in the gushing well, accusing BP of gross negligence in operating the drilling rig.

Anadarko said the joint operating agreement makes BP responsible to co-owners for any damage due to gross negligence or willful misconduct.

Anadarko had no employees on the well and was a non-operating partner in the project.

The rig was owned by Transocean Ltd. of Switzerland and operated by BP.

'Fault ignored'

Meanwhile, a worker on the rig claimed, on Monday, that he found a fault in a key piece of safety equipment weeks before the disaster.

Tyrone Benton told the British Broadcasting Corporation [BBC] the fault on the Deepwater Horizon rig was not fixed and instead the device, known as a blowout preventer, was shut down and a second one used.

He said that repairing it would have meant stopping drilling work at a time when it was costing $500,000 a day to operate the rig, the source of the massive oil spill.

BP has said that rig owners Transocean were responsible for the piece of equipment, and Transocean says the device was tested successfully before the incident, the BBC reported.