Osama Bin Laden
Osama Bin Laden was unharmed and already fatally wounded when SEAL Team 6 members entered his room in Abbottabad, PakistanReuters

Contrary to the US government account, terror mastermind Osama bin Laden was not tracked down and killed in a secret operation thanks to crack American military detective work in 2011, says a Pulitzer Prize-winning journalist in an explosive new report. Instead, Pakistani officials, who knew bin Laden's whereabouts for years, aided the US, reports Seymour Hersh.

An angry White House attacked the 10,000-word article in the London Review of Books as "baseless".

"There are too many inaccuracies and baseless assertions in this piece to fact check each one," White House National Security spokesman Ned Price said in a statement.

He particularly attacked Hersh's assertion that the administration collaborated with Pakistani officials to kill the al-Qaeda boss. "The notion that the operation that killed Osama Bin Laden was anything but a unilateral US mission is patently false," said Price, who added that Pakistan only learned of the raid after the fact.

Hersh says the Pakistani officials never contradicted the White House account of what led to the raid on bin Laden's compound in Abbottabad because they didn't want to raise the ire of the many Pakistanis sympathetic to bin Laden.

He called it a "Lewis Carroll fairy tale" that bin Laden could have successfully hidden for years in a resort town 40 miles from Islamabad without officials knowing.

Hersh writes that, beginning in 2006, bin Laden was effectively under Pakistani control, kept in his Abbottabad compound with financial help from Saudi Arabia.

Officials allowed the US to carry out its operation after a source in Pakistani intelligence tipped off the Americans for a major chunk of the $25m (£16m) US reward, according to Hersh. The Obama administration has said officials received information on the terror mastermind's location through interrogations of al-Qaeda prisoners and by tracking his courier, and that he was killed in a firefight with an elite team of Navy SEALs.

The raid was in fact an intended assassination of bin Laden, reports Hersh, though two SEALs who have spoken publicly about the operation said the al-Qaeda boss died during a firefight at the compound.

Rob O'Neill Osama Bin laden
US Navy SEAL Rob O'Neill claims that he killed Osama bin Laden.Rob O'Neill/Twitter: @mchooyah

Hersh says the two nations struck a deal allowing the US to set up careful surveillance of the compound, obtaining DNA evidence confirming bin Laden's identity and even providing a Pakistani agent to help in exchange for continued American financial support of Pakistan's intelligence service and its leaders.

The reporter cites a "US major source" in his piece that the chief of staff of the Pakistani army and director general of the Inter-Services Intelligence Agency knew about the mission and worked with US officials, making sure that the two helicopters delivering the SEALs could cross Pakistani airspace without triggering any alarms.

Pakistani's former intelligence service boss Retired General Asad Durrani told him: "Look, you got the story," recounts Hersh. He said he also confirmed the information with other unnamed sources, noting to CNN that it's "very tough for guys still inside to get quoted extensively".

But CNN's Peter Bergen reported that when he contacted Durrani, the official said there was "no evidence" that Pakistan officials knew where bin Laden was hiding, but that he could "make an assessment that this could be plausible."

As part of the deal with the Pakistanis, the Obama administration was supposed to say that bin Laden had been killed in a drone strike, but after an American helicopter crashed during the raid, the White House didn't think the drone account would work, according to Hersh.

Hersh also reports that some Navy SEALs deny bin Laden was given a burial at sea in keeping with Islamic traditions, as the White House has said. Instead his remains "were thrown into a body bag and, during the helicopter flight back to Jalalaba, some body parts were tossed out over the Hindu Kush mountains," he writes.

Hersh's article strongly condemns the culture of lying in the Obama administration.

"High-level lying ... remains the modus operandi of US policy, along with secret prisons, drone attacks, Special Forces night raids, bypassing the chain of command and cutting out those who might say no," he writes.

Hersh won the Pulitzer Prize in 1970 on the My Lai massacre in which US soldiers slaughtered civilians. But his has been criticised for his extensive use of unnamed sources.