The federal government gave BP the green-light to proceed with its "top kill" procedure to put an end to the Gulf of Mexico oil spill.

Federal On-Scene Coordinator Rear Adm. Mary Landry and Adm. Thad Allen, the commandant of the Coast Guard who's been in charge of the spill response, gave BP their approval to begin their latest attempt to stop oil from pipelines the company leases from leaking into the gulf.

Their approval gives the final authorization necessary to begin the procedure, the White House said Wednesday.

The "top kill" procedure is one in which BP will seek to pump dense mud and cement into the ruptured pipeline in hopes of clogging and stopping the flow of oil into the Gulf of Mexico. While the procedure carries risks, the company has said it's optimistic that it can work.

There's political pressure on the company and administration, though, to succeed. Sen. Bill Nelson (D-Fla.) suggested Wednesday that President Barack Obama and the federal government should take over cleanup operations if the attempt fails.

The president will have an opportunity to address the aftermath of the attempt during an expected press conference Thursday at the White House.