WATCH: Biden delivers remarks after reported killing of al-Qaida leader al-Zawahri

President Joe Biden on Monday confirmed that a U.S. drone strike in Afghanistan this weekend killed al-Qaida leader Ayman al-Zawahri, declaring “justice has been delivered.”

Watch Biden’s remarks in the player above.

“This terrorist leader is no more,” Biden said in an evening speech from the White House.

Biden said U.S. intelligence officials tracked al-Zawahri to a home in downtown Kabul where he was hiding out with his family. The president approved the operation last week and it was carried out on Sunday.

The killing delivering a significant counterterrorism win just 11 months after American troops left the country after a two-decade war.

The strike, carried out by the Central Intelligence Agency, was confirmed by five people familiar with the matter who spoke on the condition of anonymity before Biden was set to brief the American people on the details of the operation in a 7:30 p.m. EDT address to the nation.

Al-Zawahri’s loss eliminates the figure who more than anyone shaped al-Qaida, first as Osama bin Laden’s deputy since 1998, then as his successor. Together, he and bin Laden turned the jihadi movement’s guns to target the United States, carrying out the deadliest attack ever on American soil – the Sept. 11, 2001, suicide hijackings.

WATCH: Biden delivers remarks after reported killing of al-Qaida leader al-Zawahri

Current and former officials began hearing Sunday afternoon that al-Zawahri had been killed in a drone strike, but the administration delayed releasing the information until his death could be confirmed, according to one person.

The house al-Zawahri was in when he was killed was owned by a top aide to senior Taliban leader Sirajuddin Haqqani, according to a senior intelligence official. The official also added that a CIA ground team and aerial reconnaissance conducted after the drone strike confirmed al-Zawahri’s death. Planning for the operation began six months ago, but intensified in the last two months, the official said.

Over the 20-year war in Afghanistan, the U.S. targeted and splintered al-Qaida, sending leaders into hiding. But America’s exit from Afghanistan last September gave the extremist group the opportunity to rebuild. U.S. military officials, including Gen. Mark Milley, chairman of the Joint Chiefs of Staff, have said that al-Qaida was trying to reconstitute in Afghanistan, where it faced limited threats from the now-ruling Taliban. Military leaders have warned that the group still aspired to attack the U.S.

The 2001 attacks on the World Trade Center and Pentagon made bin Laden America’s Enemy No. 1. But he likely could never have carried it out without his deputy. Bin Laden provided al-Qaida with charisma and money, but al-Zawahri brought tactics and organizational skills needed to forge militants into a network of cells in countries around the world.

Their bond was forged in the late 1980s, when al-Zawahri reportedly treated the Saudi millionaire bin Laden in the caves of Afghanistan as Soviet bombardment shook the mountains around them.

Zawahri, on the FBI’s Most Wanted Terrorist list, had a $25 million bounty on his head for any information that could be used to kill or capture him.

Biden spoke from the balcony off the White House Blue Room as he remains in isolation in the residence while he continues to test positive for COVID-19.