[The feed will begin at 7:30 p.m. ET]WASHINGTON — President Joe Biden will announce Monday that a CIA counterterrorism strike in Afghanistan killed al-Qaeda leader Ayman al-Zawahiri, two sources familiar with the matter told NBC News. The Associated Press first reported that al-Zawahiri was killed in the operation.The strike "was successful and there were no civilian casualties," a senior Biden administration official said earlier, without confirming the identity of the target. The official spoke on the condition of anonymity.Biden is slated to speak from the White House at 7:30 p.m. ET.Al-Zawahiri, 71, a physician and founder of the Egyptian Islamic Jihad before ascending to the top ranks in the al-Qaeda network, was one of the architects behind the devastating Sept. 11 terrorist attacks on the World Trade Center and the Pentagon. In the weeks that followed the Sept. 11 attacks, the Taliban provided sanctuary to al-Qaeda while America mobilized for what would become its longest war. Al-Zawahiri succeeded Osama bin Laden as the head of al-Qaeda in 2011.Al-Zawahiri was previously indicted by the U.S. government for his alleged role in the 1998 bombings of the U.S. Embassies in Dar es Salaam, Tanzania, and Nairobi, Kenya.The State Department had previously offered a reward of up to $25 million for information leading to his apprehension.Sunday's drone strike is the first known CIA counterterrorism operation since Kabul fell to the Taliban last year.Osama bin Laden (L) sits with his adviser Ayman al-Zawahiri, an Egyptian linked to the al Qaeda network, during an interview with Pakistani journalist Hamid Mir at an undisclosed location in Afghanistan.Visual News | Getty Images
Watch live: Biden addresses the nation after U.S. strike in Afghanistan kills top al-Qaeda leader.