U.S. Coast Guard Adm. Thad Allen said the step was taken "out of an abundance of caution" after a robotic vehicle hit a vent, closing it.
"They are checking the containment cap right now that there are no hydrates in the containment cap," Allen, the national incident commander, said. "They will attempt to reinstall the containment cap and begin producing later on today. If there are hydrates, they will probably have to rerun the pipeline, and that will take a considerable amount longer."
BP said on its Web site the lower marine riser package was removed "as a precautionary measure" to "ensure the safety of operations and allow the unexpected release of liquids to be analyzed."
"Capture of oil and gas through the LMRP cap is therefore temporarily suspended until such time that the cap can be re-installed," BP's statement said, adding the capture of oil and gas through other equipment continues.
The Transocean rig leased by BP has been spewing oil since April 20, making it the worst oil spill in U.S. history. Eleven workers died when the rig exploded.
On a somber note, Allen also said two Gulf of Mexico oil recovery workers died. One death was a swimming death while the other victim was an operator of a boat, he said.
In Washington, Interior Secretary Ken Salazar explained his decision to reinstate a moratorium on deepwater drilling that will include evidence that would "eliminate any doubt" that a moratorium was appropriate and within the department's legal authority. On Tuesday a federal judge in New Orleans issued a temporary injunction on the 6-month ban.
Speaking before a Senate Appropriations Committee subcommittee hearing Wednesday, Salazar said federal officials would look at how the moratorium in place may be refined.
"And it might be that there are demarcations that can be made based on reservoirs, when we actually do know the pressures and the risks associated with that versus those reservoirs which are exploratory in nature where you don't know as a company what it is that you are drilling in," Salazar told members of the Subcommittee on Interior, Environment and Related Agencies. "So the moratoria that we issue will include the criteria under which it is appropriate to take a look at the lifting of the moratoria."
He said officials knew conduct leading up to the Deepwater Horizon rig explosion was reckless.
"But we also know that we are not going to have a critical piece of evidence from the bottom of the ocean, the blowout preventer mechanism, that can be thoroughly examined until after we get this well killed," Salazar said. "And the killing of the well is still some 30 to 60 days away, maybe -- hopefully sooner, but we don't know."
Weather forecasters say a tropical wave in the Caribbean could move into the gulf, carrying potentially more bad news for oil cleanup efforts.
AccuWeather.com said Wednesday the strength of the system expected to enter the gulf by early next week is questionable, but there is a risk of squalls and rough seas in oil slick and cleanup-containment operation areas.