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If you live in Moscow, Chechen Islamist leader Doku Umarov would feature prominently. Many Israelis would likely include Hezbollah leader Hassan Nasrallah on their list and people living in the southern Philippines, the Abu Sayyaf group.
Some terror figures who were among the most wanted several years ago, such as Abu Anas al Libi -- who was captured last weekend in Libya -- appear not to have been active for some time. Even some terrorists try to retire. The last list compiled by CNN included senior al Qaeda operative Saif al Adel. He has vanished from the radar and may have been under house arrest in Iran.
Other figures lose relevance as their group loses territory, membership and/or funding. Groups such as al Qaeda in the Islamic Maghreb have been prone to internal rifts. Additionally, al Qaeda, especially in Pakistan, has moved away from identifying senior operational figures because of the effects of U.S. drone strikes, so some of a new generation of most dangerous terrorist figures may not yet be known to us.
The following selection is intended neither as definitive nor a "league table." It focuses not on organizations but on men (and they are all men) alleged to be plotting, directing -- and in some instances carrying out -- acts of terror aimed at causing mass casualties among civilians.
Some are ideologues and planners, others "operational," and some are both. They think and act in a regional and in some cases a global context. Some of the individuals below have appeared on previous lists compiled by CNN and others, and have lived long enough to warrant a second or third appearance.
Others are only now making a name for themselves among the world's counterterrorism agencies, as they take advantage of conflict or the collapse of state authority, forge new alliances or develop new ways of bringing terror to the international stage.
Despite the whittling away by drone attacks of "al Qaeda central" in the mountainous border region between Afghanistan and Pakistan, the group's leader remains vocal and active in trying to harness the disparate affiliates that claim the al Qaeda name.
Since former leader Osama bin Laden's death in 2011, al-Zawahiri has sought to take advantage of the unrest sweeping the Arab world, and has recognized that groups such as al Qaeda in the Arabian Peninsula (AQAP) and al Qaeda in the Islamic Maghreb are better placed to carry out attacks than the ever-diminishing core that remains in "Af-Pak." At times, al-Zawahiri has struggled to exercise authority over groups such as the Islamic State in Iraq, not least because of the difficulty in communicating with far-flung offshoots.
Aware that pulling off another 9/11 is a remote possibility, al-Zawahiri has suggested a shift to less ambitious and less expensive but highly disruptive attacks on "soft" targets, as well as hostage-taking. In an audio message in August he recommended taking "the citizens of the countries that are participating in the invasion of Muslim countries as hostages."
Al-Zawahiri, an Egyptian doctor who is now 62, is not the inspirational figure to jihadists that bin Laden was, but he is trying to fashion a role as the CEO of a sprawling enterprise. According to the Economist, he may be succeeding. "From Somalia to Syria, al-Qaeda franchises and jihadist fellow travellers now control more territory, and can call on more fighters, than at any time since Osama bin Laden created the organisation 25 years ago," it wrote this month.
Reward offered by the U.S. government for his capture: up to $25 million
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