WASHINGTON: The Central Intelligence Agency (CIA) has marked the anniversary of the killing of Osama bin Laden by live-tweeting ─ with a five-year delay ─ the raid by United States (US) special forces on the Al Qaeda founder's compound in Abbottabad.

Using the hashtag #UBLRaid, the CIA blasted out updates of the May 2011 strike as if it was unfolding in real time ─ in a highly unusual move for the secretive spy agency.

“To mark the 5th anniversary of the Usama Bin Ladin operation in Abbottabad we will tweet the raid as if it were happening today. #UBLRaid,” @CIA said, announcing its social media blitz.

Read: Osama bin Laden killed in Pakistan, says Obama

Tweets included the now famous picture of President Barack Obama and other high-ranking US officials watching matters unfold from the White House's Situation Room.

The raid

The President Barrack Obama, Director CIA Panetta and Joint Special Operations Command's Admiral McRaven approve Operation Neptune Spear, the operation to neutralise bin Laden.

After receiving go-ahead, helicopters from the 160th Special Operations Aviation Regiment (160 SOAR), also known as 'Nightstalkers', departed from their staging area in Afghanistan. Onboard were special operation troopers from SEAL Team Six.

The two helicopters, designed to be quiet and to have low radar visibility, descended on the Abbotabad compound. One of the helicopter's crashed while landing, but the force initiated the assault without suffering any delay or injury.

Obama, along with his close associates, watched the operation live. The feed was generated by surveillance assets circling above the compound and was also provided by cams mounted on SEAL helmets.

Osama bin Laden was found and killed on the third floor, in the compound's main building.

The assault team, while conducting a sweep of the compound, found a sizeable quantity of intelligence material.

Obama also received a tentative confirmation of bin Laden's death.

Later, the first helicopter left the compound for Afghanistan, and another helicopter was dispatched to pick up the remaining members of assault force.

The SEAL team also destroyed the wreckage of the helicopter that crashed earlier, in order to deny the technology used in the previously unseen MH-60 Stealth Hawk helicopter.

President Obama received confirmation, with high probability, of Osama's death at around 7am US time.

The planning

The SEAL assault team conducted practice-runs of the attack plan on a life size replica of the Abbottabad compound. The replica had movable walls, to counter any change in the internal layout of the main structure.

The replica also featured high walls topped with barbed wire, double entry gates and no internet or phone connections.

Twitter reacts

The CIA's Twitter move got quite a bit of attention, with not everyone enthused.

“@CIA Are we tweeting Hiroshima on August 6th too? Or is THAT in bad taste?” tweeted one user, Kris Knight.

Another who identifies as Amber V tweeted: “Don't you have better things to do, like catch living and breathing bad guys, or secretly invade our privacy, or something? @CIA#UBLRaid."

But others reacted positively.

“Watching the @CIA relive on Twitter the #UBLRaid today reminds me of how proud I am of the men and women who do what they do. Thank you,” tweeted Toby Knapp.

CIA focus on al-Baghdadi

With 1.33 million Twitter followers, the CIA has sent 1,662 tweets since it joined the social media service in February 2014.

“We are the nation's first line of defense. We accomplish what others cannot accomplish and go where others cannot go,” reads the Twitter bio.

Previous @CIA tweets in recent days have featured a video about the Chernobyl nuclear accident in Ukraine and a counterfeit Nazi stamp.

Amid the tweetstorm, CIA chief John Brennan said Sunday that taking out the head of the militant Islamic State (IS) group would have a “great impact."

He also warned that Al Qaeda remained a threat, and that IS was not just an organisation but a phenomenon.

“We have destroyed a large part of Al Qaeda. It's not completely eliminated. So we have to stay focused on what it can do,” Brennan told NBC's “Meet the Press” talk show.

“Now, with the new phenomenon of (IS), this is going to challenge us for years to come,” he added.

Asked if removing IS leader Abu Bakr al-Baghdadi from action was as important as the Bin Laden get, Brennan, who does not often do interviews, was direct.

“If we got Baghdadi, I think it would have a great impact on the organisation. And it will be felt by them,” he said.