NEW ORLEANS (AP) — Pressure readings have been less than ideal from the new cap shutting oil into BP’s busted well, but the crude will remain locked in while engineers look for evidence of whether there is an undiscovered leak, the federal point man for the disaster said Friday.

Retired Coast Guard Adm. Thad Allen said on a conference call that pressure readings from the cap have not reached the level that would show there are no new leaks in the well.

Allen said BP’s test of the cap, which started 24 hours previously by shutting three valves and stopping the flow of oil into the water, would continue for at least 6 hours. It was scheduled to last up to 48 hours.

He said the developments were ‘‘generally good news’’ but needed close monitoring.

Allen said there are two possible reasons being debated by scientists on the project for why the pressure hasn’t risen as high as desired: The reservoir that is the source of the oil could be depleting after a three-month spill, or there could be an undiscovered leak somewhere down in the well.