According to US media outlets, the US killed Al-Qaeda chief Ayman al-Zawahiri in what the White House called a "successful" operation against a target in Afghanistan on Monday. 

Zawahiri, an Egyptian surgeon who became one of the world's most wanted terrorists, was identified as the mastermind behind September 11, 2001, terrorist attacks on the United States, which killed nearly 3,000 people.

He had been on the run since then and took over Al-Qaeda after Osama bin Laden was assassinated in Pakistan in 2011. A $25 million bounty had been placed on his head by the United States.

Despite a $25 million US bounty on his head, al-Zawahiri apparently felt secure enough in the Taliban's takeover of Afghanistan to relocate to Kabul and live on his balcony.

However, the US government had not given up on pursuing one of the September 11, 2001 attack planners and Osama bin Laden's heir.

After years of searching, US forces launched two Hellfire missiles from a drone flying above Kabul, striking Zawahiri's safe house and killing him, President Joe Biden said on Monday.

According to US officials, the operation that killed bin Laden in his Pakistan hideout in 2011 was meticulously planned.

The presence of the violent jihadist group's leader in Afghanistan was unsurprising: analysts say Al-Qaeda has felt more at home in Afghanistan since the hardline Islamist Taliban regained control in August.

But finding him was still difficult.

"The US government has been aware for several years of a network that we assessed supported Zawahiri," a senior administration official told reporters.

But it wasn't until this year that US intelligence learned that his family had relocated to Kabul, including his wife, daughter, and her children.

They were cautious, according to the official, using "longstanding terrorist tradecraft" to avoid being tracked down to the Qaeda leader.

Nonetheless, Zawahiri eventually arrived and never left.

"We identified Zawahiri for sustained periods of time on the balcony on multiple occasions," the official said.

During the months of May and June, an attack strategy was developed. The US was constantly monitoring the multi-story residence — exactly as the official would not say — in order to understand the family's way of life.

Detailed safe-house design
To reduce the risk to civilians, they studied the home's construction, aiming to hit Zawahiri without jeopardizing the building's structural integrity.

Defense and intelligence officials completed the plan in June and presented it to Biden in the White House on July 1, using a detailed model of the residence, just as they had done before the bin Laden raid.

According to the official, Biden asked detailed questions about the structure, weather issues, and the risk to civilians.

Finally, on July 25, while still sick with Covid-19, Biden made the decision.

The final briefing was attended by key cabinet officials, echoing April 28, 2011, White House meeting at which President Barack Obama decided to send US special operations troops into Pakistan to capture bin, Laden.

Biden was a vice president at the time, and he expressed reservations. He later recalled that the risks of things going wrong were high, that bin Laden had not been clearly identified, and that relations with Pakistan could suffer.
However, with Zawahiri, no US troops would enter the country; Zawahiri was clearly identified, and relations with the Taliban were almost non-existent.

At the end of the discussion on the 25th, Biden, like Obama, asked each participant for their thoughts.

"All strongly recommended approval of this target," the official said, and Biden agreed.

 A US drone armed with two precision-guided Hellfire missiles launched the strike at 6:18 a.m. Sunday, Kabul time.

 According to the official, Zawahiri was "killed on the balcony."

 The missiles did not appear to be standard Hellfires, whose high explosives could have destroyed the house.

'A significant setback for Al-Qaeda'
Photographs of the structure show only a few windows on one floor blown out, with the rest intact.

That suggests the use of a non-explosive Hellfire variant, the R9X, which deploys a series of knife-like blades from its fuselage and shreds its target while leaving nearby people and objects unharmed.

US forces have used the so-called "flying Ginsu" missile at least a half-dozen times to kill other jihadist group leaders while causing no harm to bystanders.

The official did not provide specifics but expressed certainty that Zawahiri had been killed and that no one else had been injured.

"Zawahiri's family members were present in other parts of the safe house at the time of the strike and were purposefully not targeted or harmed," he explained.

The strike "deals a significant blow to Al-Qaeda and will degrade the group's ability to operate," according to the official.

"As President Biden has repeatedly stated, we will not allow Afghanistan to become a safe haven for terrorists who may harm Americans," the official stated.