BP says there are no signs of leakage from its ruptured oil well in the Gulf of Mexico, a day after the flow was stopped for the first time since April.
No oil has escaped from the new cap sealing the well and there was no sign of any breach under the sea floor, BP executive Kent Wells said.
However, more pressure testing is being done to check there are no ruptures.
Earlier, the US official overseeing the spill response, Adm Thad Allen, said the latest tests were inconclusive.
Adm Allen said the pressure test of the well would continue for several more hours.
Speaking in Washington on Friday, US President Barack Obama cautioned against over-optimism and said much work remained to be done.
“It is important we don’t get ahead of ourselves,” he said.
“One of the problems with having this camera down there is, is that when the oil stops gushing, everybody feels like we’re done – and we’re not.”
A new cap was used on Thursday to stop the flow for the first time since 20 April, as part of a 48-hour test of the well’s integrity.
Eleven workers were killed in the Deepwater Horizon explosion, and the oil spill has caused an environmental catastrophe, killing wildlife and coating fragile coastal marshlands with thick, brown crude.
Spilled oil has affected hundreds of miles of Gulf coastline since April, with serious economic damage to the region as tourists have avoided Gulf Coast beaches and fishing grounds have remained closed.
BP has already paid out more than $200m (