US President Joe Biden announced Monday that Al-Qaeda leader Ayman al-Zawahiri had been killed in a US drone strike in Kabul over the weekend.

In an evening address from the White House, Biden said the "successful operation" was carried out after US intelligence officials tracked al-Zawahiri to a home in downtown Kabul where he was hiding out with his family.

In his Monday remarks, the US president said the operation delivered justice and hopefully “one more measure of closure” to families of the victims of the Sept. 11, 2001, attacks. The US president said the drone strike was "carefully planned" in order to minimize the risk to civilians, and when he was advised last week that "conditions were optimal," he gave final approval.

"None of his family members were hurt, and there were no civilian casualties," Biden added.

The drone attack was carried out by the Central Intelligence Agency (CIA), according to five people familiar with the matter who spoke to Associated Press on the condition of anonymity.

However, neither Biden nor the White House detailed the CIA’s involvement in the strike.cks on the US.

Al-Zawahiri, 71, was "deeply involved" in the planning of the Sept. 11 attacks, Biden said, and was the "mastermind" of the 2000 bombing of the USS Cole, which killed 17 American sailors.

He also described the operation as a proof 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."

Reuters has described Al-Zawahiri's death as the biggest blow to Al-Qaeda since its founder Osama bin Laden was killed in 2011.

There has been no official reaction from Iran to Biden's announcement, although Tehran accuses Washington of waging 20 years of war and causing bloodshed in Afghanistan. Initial media reports in government newspapers were mostly neutral.

Saudi Arabia, however, expressed satisfaction. In a statement its foreign ministry said, "Zawahiri is considered one of the leaders of terrorism that led the planning and execution of heinous terrorist operations in the United States and Saudi Arabia."

In August 2021 the Biden administration failed to organize an orderly US withdrawal from Afghanistan, which brought on harsh criticism by many Americans and his Republican opposition. The killing of al-Zawahiri can partly erase the memory of the withdrawal debacle.