JOIN USSeepage found 1.9 kilometres from the capped well was not related to the operation to staunch the flow of oil from the wellhead, said US Coast Guard admiral Thad Allen.
"We do not believe that is associated with this particular well integrity test," Allen, the US pointman in charge of the government's response to the disaster, told reporters yesterday.
"At this point there is not any reason to believe that we have anything that's a major issue in relation to the well's integrity from the seepages we've located."
Days of testing by BP and the government since the cap was closed off had picked up other "anomalies" a few hundred meters from the well, and showed there was "some leakage in the capping stack" atop the well head.
But Allen stressed "we do not believe this is consequential at this time."
BP wants to keep the valves on its containment cap closed continuously until an operation to permanently seal the well can be performed in less than two weeks time, meaning no more toxic crude would stream into the Gulf.
But the government is granting extensions only in 24-hour increments and has ordered the British energy giant to be ready to remove the cap immediately if the seepage is confirmed to be methane.
Measuring devices on BP's cap have given steadily increasing high-pressure readings since tests began Thursday, indicating there are no major leaks in the wellbore.
"The pressure sits at 6,811 pounds per square inch and continues to gradually rise several pounds or a pound or so every hour. And that's a positive trend," Allen said.