BP extends Gulf well test 24 hours: U.S.

"We've found nothing that would be consequential toward the integrity of the wellhead to date," retired Coast Guard Admiral Thad Allen told reporters at a briefing in Washington.

He said BP and government scientists were in talks about bolstering a relief well's role in intercepting and killing the leak with a "static kill," or an effort to pump heavy drilling mud and cement into the blown well from the top as well as through the relief well at the bottom.

With the leak capped, "We could probably overcome the hydrocarbons that are in there," Allen said.

He also said officials are closely watching a weather system near Puerto Rico that could strengthen into a tropical depression and possibly interfere with operations at the spill site.

(Reporting by Jeremy Pelofsky in Washington and Kristen Hays in Houston, Editing by Sandra Maler and Vicki Allen)