A US weekend strike in Afghanistan has killed top al-Qaida leader Ayman al-Zawahiri, according to multiple media reports. The White House announced on Monday afternoon that Joe Biden will address the nation on Monday evening about “a successful counter-terrorism operation”, but without naming an individual. A senior US official told Reuters that over the weekend, the US conducted a successful operation against a “significant al-Qaida target” in Afghanistan and that there were no civilian casualties in the operation, the news agency separately reported. Several outlets have named the target as al-Zawahiri, who had been the No 2 al-Qaida leader to Osama bin Laden and was understood to have taken over when the man who ran the terrorist organization during the September 11, 2001 attacks on the US was killed by US special forces in 2011 during the administration of Barack Obama. Al-Zawahiri was killed in a CIA drone strike in Afghanistan, unnamed US officials told Reuters on Monday in the biggest blow to the fundamentalist Islamist organization since the death of bin Laden. One of the officials, speaking on the condition of anonymity, said a drone strike was carried out by the CIA in the Afghan capital Kabul on Sunday. In a statement, Taliban spokesman Zabihullah Mujahid confirmed that a strike took place and strongly condemned it, calling it a violation of “international principles”. Zawahiri, an Egyptian doctor and surgeon, helped coordinate the 9/11 attacks in which four civilian aircraft were hijacked and crashed into the World Trade Center’s twin towers in New York, the Pentagon near Washington and a Pennsylvania field, killing nearly 3,000 people. He had a $25m bounty on his head. It was not immediately clear how the US, which does not have its troops on the ground, confirmed that Zawahiri had been killed. His death raises questions about whether Zawahiri received sanctuary from the Taliban following their takeover of Kabul in August 2021. The drone attack is the first known US strike inside Afghanistan since US troops and diplomats left the country in August 2021. Advertisement The United Nations reported last month that Al-Qaida has a haven in Afghanistan under the Taliban and “increased freedom of action” with the potential of launching new long-distance attacks in coming years, according to a report from the international body, based on intelligence supplied by member states. The assessment, by the UN committee charged with enforcing sanctions on the Taliban and others that may threaten the security of Afghanistan, raised concerns that the country could once again become a base for international terrorist attacks after the rapid and chaotic withdrawal of US and Nato troops last year. Though al-Qaida has been overshadowed by the violence of Islamic State in recent years, it remains a potential threat with a presence in parts of south Asia, the Middle East and the Sahel. Several dozen al-Qaida senior leaders are based in Afghanistan, as well as affiliated groups such as al-Qaida in the Indian subcontinent. The Taliban have repeatedly said they are adhering to an agreement they signed with the US in 2020, before taking power, in which they promised to fight terrorists, and they have insisted Afghanistan will not be used as a launching pad for attacks against other countries. The report credits the Taliban with making efforts to restrain al-Qaida, but raises concerns that these may not last. An undisclosed number of al-Qaida members are reported to be living in Kabul’s former diplomatic quarter, where they may have access to meetings at the foreign affairs ministry, the report’s authors say, although they say this information is not confirmed. The report also said a sudden spate of statements and communications from al-Qaida’s leader, Ayman al-Zawahiri, had suggested at the time that “he may be able to lead more effectively than was possible before the Taliban takeover of Afghanistan”.