US President Barack Obama has said it is "way too early to be optimistic" as he makes his third visit to the oil-hit Gulf of Mexico coast.
Earlier BP expressed confidence that a new cap placed over the ruptured well in the Gulf would capture most of the leaking oil.
But it said it could...
Oil giant BP says it is unsure whether its latest attempt to plug a gushing oil well in the Gulf of Mexico has succeeded.
Chief operating officer Doug Suttles said the "top kill" operation had not yet stopped the flow and it was preparing its next plan.
Millions of gallons of oil have leaked...