NEW ORLEANS (AP) — The government official overseeing the Gulf oil spill response said Saturday he wants additional tests done before ordering BP to finish drilling a relief well that will help plug the runaway well for good.

Retired Coast Guard Adm. Thad Allen told reporters it could be late Monday or early Tuesday before officials know the results of those tests, which will be designed to minimize any potential risks with the final plugging procedure.

If Allen gives his final order to proceed with the relief well then, it could be next weekend before the relief well intercepts the blown-out well. Once that happens, engineers will pump in mud and cement to plug the well from below, a process known as the bottom kill.

Before that happens, Allen wants to know if pressure inside the well has to be decreased. He has instructed BP to provide an analysis to determine if the bottom kill could risk damaging the well further without some kind of pressure relief.

BP began drilling its primary relief well in early May to permanently seal the ruptured well. But about two weeks ago, around the time the company had done a successful static kill pumping mud and cement into the top of the well, executives began signaling that the bottom kill procedure might not be done. In recent days, Allen suggested that was a possibility.

But pressure tests this week reaffirmed the original plan.

‘‘The relief well will be finished and the bottom kill will be executed,’’ he said.

A month after plugging the wellhead in the Gulf of Mexico, the waters that were once blackened with gushing crude are now a clear mossy green, lapping the sides of ships stationed near the wellhead.

On Saturday, the only dark shadows on the water appeared to be caused by clouds in an otherwise clear sky.

Despite the end of the immediate disaster, however, about a dozen ships are located near the relief wells, overseeing undersea robots and standing by to help with any containment needs that might arise.

Several miles away, a National Oceanic and Atmospheric Administration research vessel had been slowly circling the site, using sonar to search for undersea oil leaks that might have been pushed up from the pressure of the cap on the wellhead. The ship has taken 384 water samples since July 28 that were being sent back to a lab to be tested for oil and, if necessary, matched to the same crude that had soiled the Gulf.

So far, Anne K. Lynch, commanding officer of the Henry B. Bigelow, said crews have not found anything to suggest a significant leak since the July 15 blocking of the crude from gushing into the Gulf.

‘‘There’s nothing scary,’’ she said.

Allen also said that BP’s failed blowout preventer may be replaced before the relief well is completed. He said when it is replaced, officials will take precautions to preserve it for evidence.

Investigators want to analyze the contraption to determine why it failed to prevent the Deepwater Horizon explosion April 20 that killed 11 workers and caused 206 million gallons of oil to spew from the well a mile beneath the surface of the Gulf of Mexico.

Meanwhile, BP warned residents of the Gulf region to watch out for scammers posing as company employees and seeking personal information or money for ‘‘safety training’’ and other purposes.

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Associated Press Writer Noaki Schwartz contributed to this report from aboard the NOAA ship Henry B. Bigelow.