"My fellow Americans, on Saturday at my direction, the United States successfully concluded an airstrike in Kabul, Afghanistan, that killed the amir of al-Qaida, Ayman al-Zawahiri," he said.
"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," Biden added.
Al-Zawahiri is believed to be one of the central planners behind the Sept. 11, 2001, terrorist attacks on the World Trade Center and the Pentagon. He was a physician and founder of the Egyptian Islamic Jihad before taking over the top ranks of the al-Qaida network.
Biden said that al-Zawahiri, while in hiding, coordinated al-Qaida's branches throughout the world and "was the mastermind behind attacks against Americans," including the bombing of the USS Cole in 2000, which killed 17 U.S. sailors and wounded dozens more, as well as bombings of the U.S. embassies in Kenya and Tanzania that killed 224 people and wounded more than 4,500 others.
"Now justice has been delivered, and this terrorist leader is no more," Biden said. "People around the world no longer need to fear the vicious and determined killer. The United States continues to demonstrate our resolve and our capacity to defend the American people against those who seek to do us harm."
The strike is the first attack in Afghanistan since U.S. forces left last year under an agreement first agreed to by then-President Donald Trump and the Taliban.
In return for the exit of U.S. troops, the Taliban agreed to prevent Afghan soil to be used by any international terrorist group or individuals against the United States.
"They also betrayed the Afghan people and their own stated desire for recognition from and normalization with the international community," Blinken said. "In the fact of the Taliban's unwillingness or inability to abide by their commitments, we will continue to support the Afghan people with robust humanitarian assistance and to advocate for the protection of their human rights, especially of women and girls."
The Taliban condemned the operation in a statement, also accusing the United States of violating the Doha Agreement.
"The security and intelligence agencies of the Islamic Emirate investigated the incident and found that the attack was carried out by American drones," said the translated tweet from Taliban spokesman Zabihullah Majuhid. "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."
U.S. officials said the strike was not conducted by the military but was carried out by the Central Intelligence Agency.
"The strike that killed al-Qaida leader Ayman al-Zawahiri is a major success of U.S. counterterrorism efforts," Mick Mulroy, a former CIA. officer and senior Pentagon official, told The New York Times. "A result of countless hours of intelligence collection over many years. He likely believed we would never be able to track him down. But he was wrong."
Biden said the United States would continue to "vigilantly monitor and address threats from al-Qaida, no matter where they emanate from."
Sen. Ted Cruz, R-Texas, praised al-Zawahiri's death as "an important accomplishment."
"All Americans will breathe easier today knowing Ayman al-Zawahiri, the leader of al-Qaida, has been eliminated," he said in a statement. "This strike should be a message to terrorists near and far: If you conspire to kill Americans, we will find and kill you."
Sen. Rob Portman, R-Ohio, similarly praised the man's death as "great news" for the United States and its national security.
"I commend the determined efforts of our counterterrorism professionals for their excellent work in locating Zawahiri and removing him from the battlefield," he tweeted. "May they have similar success bringing other al-Qaida leaders to justice."