A former Egyptian special forces officer and high-ranking member of al-Qaeda is now the "uncontested" leader of the militant group.
Saif Al-Adel, who is on the FBI's most wanted list with a $10million US bounty on his head, has taken over the organisation's leadership, according to a UN report.
Al Qaeda has not formally named a successor for Ayman al-Zawahiri, who was believed to have been killed in a US missile strike in Kabul last year, dealing a blow to the organisation since its founder Osama bin Laden was killed in 2011.
In November and December discussions, many UN states took the view that Seif al-Adel is already operating as the de facto and uncontested leader of the group, as stated in the United Nations report assessing risks from the group.
Adel planned attacks from the shadows, unlike his slain predecessors who maintained a high profile with fiery videos broadcast around the globe threatening the United States.
He is sought in connection with the August 7, 1998, bombings of the United States Embassies in Dar es Salaam, Tanzania, and Nairobi, Kenya, that killed 224 civilians and wounded more than 5,000 others.
According to US investigators, little else is known about Adel, aside from his training camps and link to the killing of US journalist Daniel Pearl in Pakistan in 2002.
The US State Department says Adel is based in Iran, living under the protection of the country's Islamic Revolutionary Guard Corps.
Adel began his long career suspected of involvement in the assassination of Egyptian President Anwar al-Sadat during a military parade in Cairo that was broadcast on television.
"Seif al-Adel's professional military background and valuable experience as the head of al Qaeda's military committee prior to 9/11 mean he has strong credentials to assume the overall leadership of al Qaeda," said Elisabeth Kendall, a jihad expert at Oxford University.
Experts on the jihadi movement say that Adel takes over an Al-Qaeda which has become highly decentralised since the group carried out its most spectacular operation, the September 11, 2001 aeroplane attacks against the United States which killed nearly 3,000 people.
Adel has many aliases. He is also known as Muhamad Ibrahim Makkawi, Seif Al Adel, Ibrahim Al-Madani, and Muhamad Salah al-din al-Halim Zaydan.
His date of birth is either April 11, 1963, or April 11, 1960, and he was born in Egypt.
Al-Adel is an al-Qaeda senior leader based in Iran and a leader of the Hittin Committee, which governs and coordinates the group's transnational activities.
He is wanted for conspiracy to kill United States nationals, to murder, to destroy buildings and property of the United States, and to destroy the national defence utilities of the United States.
The Rewards For Justice Program, United States Department of State, is offering a reward of up to $10 million for information leading directly to the apprehension or conviction of Saif Al-Adel.
He should be considered armed and dangerous, and if you have any information concerning this person, please contact your local FBI office or the nearest American Embassy or Consulate.
A description of him by the FBI includes Al-Adel's photograph taken in Tehran, Iran, in 2012.
His physical characteristics, including height, weight, and build, are unknown, according to the FBI's description.
He also has an olive complexion, dark hair, and dark eyes, and speaks Arabic, while there are no known scars or marks on his body.
