(CNN) The United States killed al Qaeda leader Ayman al-Zawahiri in a drone strike, President Joe Biden said Monday in a speech from the White House.
"I authorized a precision strike that would remove him from the battlefield, once and for all," Biden said.
Zawahiri, who just turned 71 years old, had remained a visible international symbol of the group, 11 years after the US killed Osama bin Laden. At one point, he acted as bin Laden's personal physician.
Zawahiri was sheltering in downtown Kabul to reunite with his family, Biden said, and was killed in what a senior administration official described as "a precise tailored airstrike" using two Hellfire missiles. The drone strike was conducted at 9:48 p.m. ET on Saturday was authorized by Biden following weeks of meetings with his Cabinet and key advisers, the official said on Monday, adding that no American personnel were on the ground in Kabul at the time of the strike.
Senior Haqqani Taliban figures were aware of Zawahiri's presence in the area, the official said, in "clear violation of the Doha agreement," and even took steps to conceal his presence after Saturday's successful strike, restricting access to the safe house and rapidly relocating members of his family, including his daughter and her children, who were intentionally not targeted during the strike and remained unharmed. The US did not alert Taliban officials ahead of Saturday's strike.
In a series of tweets, Taliban spokesman Zabiullah Mujahid said, "An air strike was carried out on a residential house in Sherpur area of Kabul city on July 31."
He said, "The nature of the incident was not apparent at first" but the security and intelligence services of the Islamic Emirate investigated the incident and "initial findings determined that the strike was carried out by an American drone."
The tweets by Mujahid came out prior to CNN reporting Zawahiri's death. Mujahid said the Islamic Emirate of Afghanistan "strongly condemns this attack on any pretext and calls it a clear violation of international principles and the Doha Agreement."
Biden, who was kept abreast of the strike against Zawahiri as he isolated with a rebound case of Covid-19, spoke outdoors Monday from the Blue Room Balcony at the White House.
Zawahiri, Biden said, "was deeply involved in the planning of 9/11, one of the most responsible for the attacks that murdered 2,977 people on American soil. For decades, he was the mastermind of attacks against Americans."
"Now, justice has been delivered and this terrorist leader is no more. People around the world no longer need to fear the vicious and determined killer," he continued. "The United States continues to demonstrate our resolve and our capacity to defend the American people against those who seek to do us harm. We make it clear again tonight, that no matter how long it takes, no matter where you hide, if you are a threat to our people, the United States will find you and take you out."
The President said the precision strike targeting was the result of the "extraordinary persistence and skill" of the nation's intelligence community.
"Our intelligence community located Zawahiri earlier this year -- he moved to downtown Kabul to reunite with members of his immediate family," Biden said.
The strike comes one year after Biden ordered the withdrawal of US troops from Afghanistan, prompting Taliban forces to rapidly seize control of the nation.
Biden said on Monday that when he withdrew US troops from the country, he "made the decision that after 20 years of war, the United States no longer needed thousands of boots on the ground in Afghanistan to protect America from terrorists who seek to do us harm, and I made a promise to the American people, that we continue to conduct effective counterterrorism operations in Afghanistan and beyond. We've done just that."
Biden pledged that Zawahiri "will never again allow Afghanistan to become a terrorist safe haven, because he is gone and we're going to make sure that nothing else happens."
The President concluded by expressing gratitude to US intelligence and counterterrorism communities, saying that he hopes Zawahiri's death will bring some measure of closure to the friends and families of 9/11 victims.
"To those who continue to seek to harm the United States, hear me now: We will always remain vigilant and we will act -- and we will always do what is necessary to ensure the safety and security of Americans at home and around the globe," he concluded.
A senior counterterrorism analyst told CNN that it would have been impossible for Zawahiri to be in Kabul without the invitation and acquiescence of at least a small number of Taliban, whether from the Haqqani network or another part of the group.
The analyst said that this strike was embarrassing for the Taliban as they had claimed there were no foreign fighters in Afghanistan and no al Qaeda.
He added that recent statements from Zawahiri had suggested the al Qaeda leader was feeling more relaxed. The statements had referred to more recent events, the analyst said, adding this potentially revealed a complacency that may have led to the successful strike.
The issue now arises as to who will be Zawahiri's successor.
The current al Qaeda No. 2, Saif al Adel, is thought to have been in Iran, according to United Nations reports.
The analyst said that this raised an urgent issue for the Iranians who now have to choose between expelling the new al Qaeda leader or harboring him.
A former official in the Afghan government with an intimate grasp of counterterrorism said that he had heard al Adel had already left Iran for Afghanistan.
Zawahiri comes from a distinguished Egyptian family, according to the New York Times. His grandfather, Rabia'a al-Zawahiri, was an imam at al-Azhar University in Cairo. His great-uncle, Abdel Rahman Azzam, was the first secretary of the Arab League.
He eventually helped to mastermind the deadliest terror attack on American soil, when hijackers turned US airliners into missiles.
"Those 19 brothers who went out and gave their souls to Allah almighty, God almighty has granted them this victory we are enjoying now," al-Zawahiri said in a videotaped message released in April 2002.
It was the first of many taunting messages the terrorist -- who became al Qaeda's leader after US forces killed bin Laden in 2011 -- would send out over the years, urging militants to continue the fight against America and chiding US leaders.
Zawahiri was constantly on the move once the US-led invasion of Afghanistan began after the September 11, 2001, attacks. At one point, he narrowly escaped a US onslaught in the rugged, mountainous Tora Bora region of Afghanistan, an attack that left his wife and children dead.
He made his public debut as a Muslim militant when he was in prison for his involvement in the 1981 assassination of Egyptian President Anwar Sadat.
"We want to speak to the whole world. Who are we? Who are we?" he said in a jailhouse interview.
By that time, al-Zawahiri, a young doctor, was already a committed terrorist who conspired to overthrow the Egyptian government for years and sought to replace it with fundamentalist Islamic rule. He proudly endorsed Sadat's assassination after the Egyptian leader made peace with Israel.
He spent three years in prison after Sadat's assassination and claimed he was tortured while in detention. After his release, he made his way to Pakistan, where he treated wounded mujahadeen fighters who fought against the Soviet occupation of Afghanistan.
That was when he met bin Laden and found a common cause.
"We are working with brother bin Laden," he said in announcing the merger of his terror group, Egyptian Islamic Jihad, with al Qaeda in May 1998. "We know him since more than 10 years now. We fought with him here in Afghanistan."
Together, the two terror leaders signed a fatwa, or declaration: "The judgment to kill and fight Americans and their allies, whether civilians or military, is an obligation for every Muslim."
The attacks against the US and its facilities began weeks later, with the suicide bombings of US embassies in Kenya and Tanzania that killed more than 200 people and wounded more than 5,000 others. Zawahiri and bin Laden gloated after they escaped a US cruise missile attack in Afghanistan that had been launched in retaliation.
Then, there was the attack on the USS Cole in Yemen in October 2000, when suicide bombers on a dinghy detonated their boat, killing 17 American sailors and wounding 39 others.
The culmination of Zawahiri's terror plotting came on September 11, 2001, when nearly 3,000 people were killed in the attacks on the twin towers of the World Trade Center and Pentagon. A fourth hijacked airliner, headed for Washington, crashed in a Pennsylvania field after passengers fought back.
Since then, al-Zawahiri raised his public profile, appearing on numerous video and audiotapes to urge Muslims to join the jihad against the United States and its allies. Some of his tapes were followed closely by terrorist attacks.
In May 2003, for instance, almost simultaneous suicide bombings in Riyadh, Saudi Arabia, killed 23 people, including nine Americans, days after a tape thought to contain Zawahiri's voice was released.
The US State Department had offered a reward of up to $25 million for information leading directly to his capture. A June 2021 United Nations report suggested he was located somewhere in the border region of Afghanistan and Pakistan, and that he may have been too frail to be featured in propaganda.
Terry Strada, the chair of 9/11 Families United -- a coalition of survivors and families of victims of the September, 11, 2001, terrorist attacks -- expressed gratitude for the strike, but called on the President to hold the Saudi Arabian government accountable for alleged government complicity in the attacks.
The group has criticized the Saudi-backed LIV Golf tour, which began its third competition at Trump National Golf Club Bedminster at the end of July -- some 50 miles from Ground Zero in Manhattan.
"I am deeply grateful for the commitment of intelligence agencies and our brave military's dedication and sacrifices made in removing such evil from our lives. But, in order to achieve full accountability for the murder of thousands on Sept. 11, 2001, President Biden must also hold responsible the Saudi paymasters who bankrolled the Attacks," Strada said in a statement.
"The financiers are not being targeted by drones, they are being met with fist pumps and hosted at golf clubs. If we're going to be serious about accountability, we must hold EVERYONE accountable," Strada added -- appearing to reference the President's controversial gesture with Saudi Crown Prince Mohammed bin Salman.
This story has been updated with additional developments on Monday.