By Peter Baker, Helene Cooper, Julian E. Barnes and Eric Schmitt

WASHINGTON — A US drone strike killed Ayman al-Zawahri, a key plotter of the Sept. 11, 2001, terrorist attacks who took over as the leader of al-Qaida after Osama bin Laden’s death, at an urban safe house in Afghanistan, President Joe Biden announced Monday (Aug 1) night.

The early-morning strike in the heart of downtown Kabul over the weekend capped a 21-year manhunt for an Egyptian radical who more than anyone besides bin Laden was deemed responsible for the deadliest foreign attack on the United States in modern times and never gave up targeting Americans.

“Now justice has been delivered, and this terrorist leader is no more,” Biden said in a seven-minute nationally televised address from the White House. “We make it clear again tonight,” he added, “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.”

US intelligence agencies tracked down al-Zawahri in Kabul earlier this year and then spent months determining that it really was him hiding out in a house in a crowded section of the Afghan capital. After receiving authorization from Biden a week ago, the CIA fired two Hellfire missiles and killed al-Zawahri on a balcony of the house without killing anyone else, including members of his family or any nearby civilians, US officials said.

The death of one of America’s most vocal enemies after a long and maddening search that stretched out over a generation was a major victory for Biden at a time of domestic political trouble. But it raised immediate questions about the terrorist leader’s presence in Afghanistan a year after Biden withdrew all US forces, clearing the way for the Taliban to recapture control of the country. Al-Zawahri moved back to Afghanistan earlier this year, evidently believing he would be safe there, officials said.

The success of the first strike since the withdrawal without US forces actually on the ground will bolster Biden’s argument that the United States can still wage war against terrorist organizations without the major deployments of ground forces that characterized the first two decades after Sept. 11.

But one of the premises of the US withdrawal was undercut by the disclosure that al-Zawahri found shelter in Afghanistan even though the Taliban had committed not to provide a safe haven for al-Qaida to launch further attacks against Americans as part of an agreement first struck by President Donald Trump and accepted by Biden.

A US official called al-Zawahri’s presence a “clear violation” of the agreement, but it was not evident what action, if any, Biden would take against the Taliban as a result.

In his short address, delivered on a White House balcony with the monuments behind him, the president vowed not to permit another sanctuary for terrorism. “We will never again, never again allow Afghanistan to become a terrorist safe haven, because he is gone and we’re going to make sure nothing else happens,” he said. “It can’t be a launching pad against the United States. We’re going to see to it that won’t happen.”

Often seen sitting by bin Laden’s side with his grey beard and fierce scowl, al-Zawahri, 71, never achieved the same global notoriety as the terrorist mastermind but was widely considered the intellectual force behind al-Qaida. An Egyptian-born Islamist who was convicted of conspiracy in the 1981 assassination of President Anwar Sadat, he later merged his organization, Egyptian Islamic Jihad, with bin Laden’s to expand its reach.

The organized and educated alter ego to bin Laden, al-Zawahri sought to rally Islamist groups into a broader jihad to kill Americans anywhere they were found, not just in the Middle East, and some counterterrorism experts believed he was even more responsible for the attacks on the United States than bin Laden.

“The strike that killed al-Qaida leader Ayman al-Zawahri is a major success of US counterterrorism efforts. A result of countless hours of intelligence collection over many years,” said Mick Mulroy, a former CIA officer and senior Pentagon official. “He likely believed we would never be able to track him down. But he was wrong.”

A statement from the Taliban condemned the operation. “It is an act against the interests of Afghanistan and the region,” the statement said. “Repeating such actions will damage the available opportunities.”

The CIA missiles hit a house in Kabul’s Sherpur area, a wealthy downtown enclave within what is considered the city’s diplomatic quarters, which once housed dozens of Western embassies and now is home to some high-ranking Taliban officials. The strike took place at 9:48 p.m. Eastern time Saturday (July 30), or 6:18 a.m. Sunday (July 31) in Kabul, officials said.

After the strike, members of the Haqqani network, a terrorist group that is part of the Taliban government, tried to conceal that al-Zawahri had been at the house and restrict access to the site, according to a senior administration official. But the official said the United States had multiple intelligence threads confirming that al-Zawahri was killed in the strike.

The Taliban have repeatedly said they are adhering to the Doha agreement and not allowing Afghanistan to become a base for attacks on other countries. But analysts and experts have warned that terrorist groups like al-Qaida and Tehrik-e-Taliban Pakistan, or the Pakistani Taliban, have found refuge in the country since the takeover.

Pakistani officials have warned that cross-border attacks launched by the Pakistani Taliban from Afghanistan surged after the Western-backed government collapsed. Between last August and the end of April, the Pakistani Taliban carried out 82 attacks in Pakistan, more than double the number over the same period of the previous year, according to the Islamabad-based Pak Institute for Peace Studies.

And this spring, a UN report warned that al-Qaida had found “increased freedom of action” in Afghanistan since the Taliban seized power. The report noted that a number of Qaida leaders were possibly living in Kabul and that the uptick in public statements by al-Zawahri suggested that he was able to lead more effectively after the Taliban seized power.

Al-Zawahri was long believed to have been living in Pakistan. That he was killed in Kabul is testament to not only the porous border between the two countries but also to al-Qaida’s decades-long use of facilities, houses, buildings and compounds throughout both countries, a U.S. official said. And unlike the relatively sleepy city of Abbottabad, Pakistan, where bin Laden was killed by a commando raid in 2011, his successor apparently spent the last weeks of his life right smack in the Afghan capital.

Earlier this year, US intelligence sources learned that al-Zawahri’s wife, daughter and grandchildren had relocated to a house in Kabul, a senior administration official told reporters during a conference call Monday night under White House ground rules requiring anonymity. The official said that the family had exercised long-standing terrorist tradecraft that was intended to prevent anyone from following them.

Still, the official said, US intelligence agencies grew increasingly confident that al-Zawahri was at the house as well. As they did in the case of bin Laden, intelligence officials used different sources and methods to build a so-called pattern of life that confirmed his presence, the official said. Once al-Zawahri arrived at the location, US officials were never aware of him leaving, and he was observed for sustained periods on the balcony where he was ultimately struck.

Two top aides to Biden — Jonathan Finer, his deputy national security adviser, and Elizabeth Sherwood-Randall, his homeland security adviser — were first briefed on the intelligence in April. Later other officials were brought in, including Jake Sullivan, the national security adviser, who briefed the president.

On July 1, CIA Director William Burns; Avril D. Haines, the director of national intelligence; Christine Abizaid, the director of the National Counterterrorism Centre; and other officials discussed the planned operation with Biden. They showed the president a model of the house al-Zawahri was staying in, and Biden asked questions about weather, construction materials, risk to civilians and other factors that could influence the success of the operation, the official said.

The strike was an important achievement for Biden, whose unpopularity in polls has jeopardized his party’s chances in the midterm elections this fall and prompted fellow Democrats to urge him to let someone else run in 2024. But such successes on the battlefield have had little lasting political benefit for his predecessors. Successful raids killing the head of the Islamic State group and a top Iranian commander made no meaningful difference for Trump, and even the raid that killed bin Laden resulted in only a temporary bump in the polls for President Barack Obama.

In the months since the United States withdrew from Afghanistan, US military and diplomatic officials have discussed with allies where to reposition US forces for strikes on high-value targets in Afghanistan. This so-called over-the-horizon strategy is still in its infancy, and talks about positioning forces in neighbouring Tajikistan, Kazakhstan and Uzbekistan have proceeded slowly.

As the United States was evacuating people from Afghanistan, a drone strike based on bad information in Kabul killed 10 civilians. The United States did not initially acknowledge the error, doing so only after reporting by The New York Times. Since then, the Pentagon and the Biden administration have been taking more precautions to prevent civilian casualties in the strikes.

Even without nearby bases, the United States has plenty of capability to send unmanned drones as well as manned attack aircraft within striking distance of Afghanistan, from land bases along the Persian Gulf, the Indian Ocean and even the United States.

An analyst said pictures of the strike posted on social media suggested a strike by an R9X, a Hellfire missile armed with long blades aimed at killing targets with kinetic energy to minimize major collateral damage.

Following the charismatic bin Laden, al-Zawahri was a competent if uninspiring leader who managed to keep together the group’s disparate global franchises even as branches in Yemen and West Africa’s Sahel region exerted more independence and authority, officials said.

Indeed, al-Zawahri’s death will most likely have little effect on the franchises’ day-to-day operations, counterterrorism experts said.

“Zawahri was far more important strategically than tactically to al-Qaida,” said Colin P. Clarke, a counterterrorism analyst at the Soufan Group, a security consulting firm based in New York. “He led the group through turbulent times, including the Arab Spring and rise of the Islamic State. He kept the organization afloat, and its affiliates and franchise groups still took strategic direction from him, even if over time they became more autonomous.”

Al-Zawahri had been much more active releasing videos in the year since the Taliban took over Afghanistan, Clarke said. The Qaida leader released a video in May speaking about the importance of jihad in Kashmir.

Under al-Zawahri’s leadership, al-Qaida’s far-flung affiliates — from Syria and West Africa to Somalia to Pakistan — enjoyed local autonomy while adhering to the leader’s overall strategy.

“Al-Zawahri was critical to al-Qaida’s survival in the decade since bin Laden’s death,” said Bruce Hoffman, a terrorism scholar at the Council on Foreign Relations. “He held the moment through his force of personality and strategic vision.”

Hoffman predicted that al-Qaida’s leadership succession would be smoother than some analysts had forecast, noting that the terrorist group now had four times as many groups following its ideology as it did on Sept. 11.

“One way or another,” he said, “the war declared by bin Laden over a quarter-century ago will continue at some level.”

-New York Times