The US government is preparing for the worst amid fears oil could gush into the Gulf of Mexico from the BP rig until August.
The White House said tonight that the amount of oil and gas leaking from BP's ruptured well could increase as much as 20% while efforts are made to cap it.
President Barack Obama was briefed by administration officials and discussed BP's efforts to put machines into place that will be used to cut the well's riser pipe so a containment device can be used to try to siphon off most of the leaking oil and gas up to a tanker ship on the surface.
'According to BP, the riser cutting will likely start Monday or Tuesday,' White House spokesman Robert Gibbs said in a statement.
National Incident Commander Admiral Thad Allen, who is in charge of the clean-up effort, said that government and contractor clean-up resources in affected areas will be tripled, as the president had directed.
Speaking on the CBS earlier, President Barack Obama's top adviser on energy and climate Carol Browner said: ‘There could be oil coming up till August when the relief wells are done.’
She said BP's latest effort to try to capture and contain oil would not provide a permanent solution or prevent some oil escaping into the sea even if the manoeuvre succeeded.
‘We are prepared for the worst. We have been prepared from the beginning', she added.
President Obama has said he 'will not relent' until the leak is contained, the water and shores are cleaned and the oil spill victims are compensated.
Mr Obama was speaking after BP's latest attempt to plug the leaking well had failed.
The so called 'top kill' procedure involved injecting thick mud and waste material into the ruptured well.
The spill began when a drilling rig exploded late last month, killing 11 people.
In an emotional statement on the setback, Mr Obama said: ‘Every day that this leak continues is an assault on the people of the Gulf Coast region, their livelihoods, and the natural bounty that belongs to all of us.
‘It is as enraging as it is heartbreaking,’ he added.
BP Chief Executive Tony Hayward had predicted that despite risks, the 'top kill' had a 60% to 70% chance of success.
He said he did not know why it failed to stop the leak.
