Oil giant BP has said that the cap over the oil leak in the Gulf of Mexico was continuing to hold.
The announcement will be greeted with cautious optimism following months of misery after the Deepwater Horizon rig exploded in April.
Integrity tests on the cap have been taking place since Thursday evening. The tests will see whether the steel casing of the cap is sufficiently strong for the well to be shut off in the long term.
Following the final test experts will begin to review the collected data to determine whether the leak has stopped for good.
A BP spokeswoman said: "The cap is still holding, integrity tests are ongoing over six-hour periods. These tests are scheduled to be completed later today but it may be some time before we know if they have been successful."
News that the leak was stopped on Thursday helped BP shares soar around 8% higher at one stage yesterday, although wider stock market falls later pared the gains back.
David Cameron met BP chairman Carl-Henric Svanberg in Downing Street on Friday to discuss the latest developments.
The spill is likely to be high on the agenda in talks with President Barack Obama when the Prime Minister makes his first official visit to Washington next week.
