A photo released by the US Coast Guard(USCG) shows fire boats battling a blaze at the BP-operated Deepwater Horizon rig off the Louisiana coastline in April 2010. BP began pumping cement into its ruptured Gulf of Mexico well Friday in a final stage procedure that should permanently seal the busted well by the weekend, the British energy giant said.

BP was set Saturday to cap a months-long effort to end the worst maritime oil spill in history with a death choke that will permanently seal its ruptured Gulf of Mexico well.

The British energy giant began pumping cement into the busted well on Friday, after which "standard plugging and abandonment procedures for the relief well" will go ahead so it can be finally, completely sealed.

"It is expected that the MC252 well will be completely sealed on Saturday," after a relief well successfully intersected the shaft this week, BP said earlier.

It said tests indicated no hydrocarbons or cement were present at the intersection of the two wells after the relief well -- one of two that have been drilling through bedrock since May -- finally intercepted the BP shaft late Thursday about 2.5 miles (four kilometers) below the .

No oil has gushed into the Gulf since July, when heavy drilling mud and cement were successfully rammed down the throat of the well from above and a cap was placed on the wellhead.

But BP and US President Barack Obama's administration have been adamant in stressing the need for the relief wells to provide a permanent solution, and to reassure Americans that BP's broken well would never again be a threat.

An estimated 4.9 million barrels (206 million gallons) of oil gushed out of the well off the coast of Louisiana after it ruptured following an April 20 explosion aboard the BP-leased Deepwater Horizon drilling rig that killed 11 workers.

It took 87 days to stem the flow of oil into the Gulf, and hundreds of miles (kilometers) of coastline from Texas to Florida were sullied, killing wildlife and devastating key local industries such as tourism and fishing.

With BP finally able to declare the well dead, the company will be able to focus its efforts on restoring a battered US Gulf Coast, where wildlife, environmentally sensitive wetlands, and major fishing and tourism industries have been devastated.

Most of the massive slick has been dispersed, dissolved, burned off or skimmed off the surface, but some scientists warn that the full impact may not be known for decades.

BP has already spent eight billion dollars trying to contain the disaster and has forecast it will eventually cost the energy giant more than 32.2 billion dollars.

On Wednesday, BP's outgoing chief Tony Hayward, who ignited American anger over his handling of the disaster, defended the firm's safety procedures to British lawmakers who grilled him over the spill and the company's response.

Hayward -- whose resignation after a string of PR gaffes takes effect on October 1 -- said the spill was "devastating" to him personally but denied that there had been any cost-cutting at the energy giant in the run-up to the accident.

He reiterated the claims in BP's own report into the disaster released earlier this month that contractors were partly to blame.

Meanwhile, the US government has said in a Louisiana court it is considering filing a civil complaint against BP under the Clean Water Act to claim 1,100 dollars for each barrel of oil spilled in the .