Al Qaeda leader Ayman al-Zawahiri has been killed by a US airstrike in Afghanistan, according to US media reports.
US president Joe Biden is set to deliver an address to the nation at 7:30pm in Washington D.C. (12.30am UK time).
The FBI was offering $25m (£20m) for “information leading to the apprehension or conviction” of the 71-year-old who was one of the masterminds of the 9/11 terror attacks.
He was also charged in the US for his alleged roles in the 7 August 1998 bombings of the US embassies in Dar es Salaam in Tanzania and Nairobi in Kenya.
A senior official in the Biden administration has said: “Over the weekend, the United States conducted a counterterrorism operation against a significant al Qaeda target in Afghanistan.
“The operation was successful and there were no civilian casualties.”
Mr Biden is due to speak 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.
The death of al-Zawahiri would be the biggest blow to al Qaeda since its founder Osama bin Laden was killed by US special forces in 2011.
A US official, speaking on the condition of anonymity, said a drone strike was carried out by the CIA in the Afghan capital Kabul on Sunday.
Taliban spokesman Zabihullah Mujahid has confirmed that a strike took place and strongly condemned it, calling it a violation of “international principles”.
Speaking on 31 August 2021, after the last US troops left Afghanistan, Mr Biden said the US would not let up on its fight against terrorism in that country or elsewhere.
“We will maintain the fight against terrorism in Afghanistan and other countries,” he said.
“We just don’t need to fight a ground war to do it.”
Previewing the strike that would occur 11 months later, Mr Biden said at the time: “We have what’s called over-the-horizon capabilities, which means we can strike terrorists and targets without American boots on the ground – or very few, if needed.”
Al-Zawahiri helped coordinate the 9/11 attacks in which four passenger aircraft were hijacked and flown into both towers of the World Trade Center in New York, the Pentagon and a field in Pennsylvania.
The terror attack left nearly 3,000 people dead on 11 September 2001.
The Egyptian had been bin Laden’s personal doctor before becoming his deputy and eventually his successor.
Al-Zawahiri was reported to be the brains behind some of the group’s grandest ambitions, including the terror group’s unsuccessful efforts to acquire nuclear and biological weapons.
In recent years he presided over al Qaeda at a time of decline, with most of the group’s founding figures dead or in hiding.