By Mohammad Yunus Yawar, Idrees Ali and Jeff Mason

KABUL/WASHINGTON (Reuters) – The United States killed al Qaeda leader Ayman al-Zawahiri with a drone missile while he stood on a balcony at his home in downtown Kabul, Afghanistan, officials in Washington said, the biggest blow to the militants since Osama bin Laden was shot dead more than a decade ago.

Afghanistan’s Taliban government has not confirmed the death of Zawahiri, an Egyptian surgeon who had a $25 million bounty on his head and helped to coordinate the Sept. 11, 2001, attacks on the United States that killed nearly 3,000 people.

U.S. officials, speaking on the condition of anonymity, said Zawahiri was killed when he came out on the balcony of his safe house in Kabul at 6:18 a.m. (0148 GMT) on Sunday morning and was hit by Hellfire missiles from a U.S. drone.

“Now justice has been delivered, and this terrorist leader is no more,” U.S. President Joe Biden said in televised remarks from the White House on Monday. “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.”

Biden said he authorised the precision strike after months of planning and that no civilians or family members were killed.

Three spokespeople in the Taliban administration, accused by the United States of violating an agreement between them by sheltering Zawahiri, declined comment on Tuesday.

Taliban spokesperson Zabihullah Mujahid previously confirmed that a strike took place in Kabul on Sunday and called it a violation of “international principles.”

A spokesperson for the interior ministry said a house was hit by a rocket in Sherpoor, a leafy, upscale residential neighbourhood in the centre of the city.

“There were no casualties as the house was empty,” Abdul Nafi Takor, the spokesperson, said.

Taliban authorities threw a security dragnet around the house and journalists were not allowed nearby.

A woman who lives in the neighbourhood and spoke to Reuters on condition of anonymity said she and her family of nine moved to the safe room of their house when she heard an explosion at the weekend. When she later went to the rooftop, she saw no commotion or chaos and assumed it was a rocket or bomb attack – which is not uncommon in Kabul.

A senior Taliban official told Reuters that Zawahiri was previously in Helmand province and had moved to Kabul after the Taliban took over the country in August last year.

White House spokesman John Kirby said the United States did not have DNA confirmation of Zawahiri’s death. “We’re not going to get that confirmation,” he said on CNN, describing “visual confirmation” along with other sources.

One senior administration official told reporters U.S. intelligence determined with “high confidence” that Zawahiri was killed.

Kirby also said there was a small al Qaeda presence remaining in Afghanistan.

“We are still going to stay vigilant, we’re still going to stay capable,” Kirby told MSNBC, adding that the United States had the capability to conduct a counter-terrorism strike from afar.

“The message has been very, very clearly sent not just to al Qaeda, but to anybody that might harbour them.”

PROVIDING SANCTUARY

After U.S. Navy SEALS shot bin Laden in Pakistan in 2011, Zawahiri succeeded him as leader. The Egyptian had previously spent years as al Qaeda’s main organiser and strategist, but a lack of charisma, and competition from rival militants Islamic State, hobbled his ability to inspire devastating attacks on the West.

There were rumours of Zawahiri’s death several times in recent years, and he was long reported to have been in poor health.

The drone attack is the first known U.S. strike inside Afghanistan since U.S. troops and diplomats left the country. The move may bolster the credibility of Washington’s assurances that the United States can still address threats from Afghanistan without a military presence in the country.

“We didn’t have any boots on the ground, but over a constant series of meticulous gathering of intelligence and information over the course of many months, we were able to execute this strike with great efficiency,” Kirby said.

Zawahiri’s death also raises questions about whether he received sanctuary from the Taliban following their takeover of Kabul. The senior U.S. administration official said senior Taliban officials were aware of his presence in the city and said the United States expected the Taliban to abide by an agreement not to allow al Qaeda fighters to re-establish themselves in the country.

U.S. Secretary of State Antony Blinken said the Taliban had “grossly violated” the Doha Agreement between the two sides by hosting and sheltering Zawahiri.

Former President Barack Obama joined lawmakers in praising the operation.

“It’s possible to root out terrorism without being at war in Afghanistan,” Obama said in a Twitter message. “And I hope it provides a small measure of peace to the 9/11 families and everyone else who has suffered at the hands of al Qaeda.”

Until the U.S. announcement, Zawahiri had been rumoured to be in Pakistan’s tribal area or inside Afghanistan.

A video released in April in which he praised an Indian Muslim woman for defying a ban on wearing an Islamic head scarf dispelled rumours that he had died.

WIFE, FAMILY IN SAME HOUSE

The senior U.S. official said the United States found out this year that Zawahiri’s wife, daughter and her children had relocated to a safe house in Kabul, then identified that Zawahiri was there as well.

He was identified multiple times on the balcony, where he was ultimately struck. He continued to produce videos from the house and some may be released after his death, the official said.

In the last few weeks, Biden convened officials to scrutinise the intelligence. He was updated throughout May and June and was briefed on July 1 on a proposed operation by intelligence leaders. On July 25, he received an updated report and authorised the strike once an opportunity was available, the administration official said.

With other senior al Qaeda members, Zawahiri is believed to have plotted the Oct. 12, 2000, attack on the USS Cole naval vessel in Yemen which killed 17 U.S. sailors and injured more than 30 others, the Rewards for Justice website said.

He was indicted in the United States for his role in the Aug. 7, 1998, bombings of the U.S. embassies in Kenya and Tanzania that killed 224 people and wounded more than 5,000 others.

Both bin Laden and Zawahiri eluded capture when U.S.-led forces toppled Afghanistan’s Taliban government in late 2001 following the Sept. 11 attacks.

(Reporting by Idrees Ali and Jeff Mason; Additional reporting by Alexandra Alper, Eric Beech, Jonathan Landay, Arshad Mohammed, Patricia Zengerle, Matt Spetalnick in Washington, Jibran Ahmad in Peshawar, Susan Heavy in Washington and Reuters staff in Kabul; Writing by Raju Gopalakrishnan and Krishna N. Das; Editing by Stephen Coates, Edmund Klamann and Frank Jack Daniel)