This slide deck presents some of the insights gleaned from a data set in Ntrepid Corporation’s Timestream application that is an open-source collection of reported ISIS-linked activity in Yemen. The full case study is available: http://www.criticalthreats.org/yemen/exploring-isis-yemen-zimmerman-july-24-2015. The Islamic State in Iraq and al Sham (ISIS) is attempting to expand its footprint in Yemen. ISIS declared an Islamic Caliphate on June 29, 2014, under the leadership of the new Caliph, ISIS leader Abu Bakr al Baghdadi. The return of the Caliphate under Baghdadi placed an obligation on all Muslims to pledge allegiance to him, according to ISIS. Al Qaeda broadly dismisses the legitimacy of the Caliphate under ISIS, and ISIS and al Qaeda are now in competition for the leadership of the global jihadist movement. Al Qaeda’s Yemen-based affiliate, al Qaeda in the Arabian Peninsula (AQAP), dominates the jihadist fight in the country and it remains the greatest direct threat to the United States from the al Qaeda network. AQAP leadership reaffirmed its allegiance to al Qaeda leader Ayman al Zawahiri in November 2014, publicly rejecting the legitimacy of the Islamic Caliphate. The 2015 collapse of the central Yemeni state created opportunities for AQAP to exploit, and the group is expanding its presence in Yemen. The initial reaction to ISIS in Yemen was muted, but the group has begun to make inroads as the conflict there protracts. ISIS began claiming regular attacks in Yemen as of March 2015 and now operates in at least eight Yemeni governorates.

1. EXPLORING ISIS IN YEMEN
Katherine Zimmerman
Critical Threats Project
American Enterprise Institute
July 24, 2015

2. EXPLORING THE RISE OF ISIS IN YEMEN
• Al Qaeda in the Arabian Peninsula (AQAP) dominates the
jihadist fight in Yemen and is the greatest direct threat to
the U.S. from the al Qaeda network.
• The Islamic State in Iraq and al Sham (ISIS) declared an
Islamic Caliphate on June 29, 2014, under the leadership of
Abu Bakr al Baghdadi. ISIS called on all Muslims to pledge
allegiance to Baghdadi.
• AQAP leadership reconfirmed allegiance to al Qaeda leader
Ayman al Zawahiri, rejecting the legitimacy of the Islamic
Caliphate in November 2014.
• The 2015 collapse of the central Yemeni state and
subsequent localized fighting has created inroads in Yemen
for both AQAP and ISIS.
• ISIS-linked cells now operate in at least eight Yemeni
governorates.
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3. UNDERSTANDING THE DATA
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ISIS STATEMENT
ISIS ATTACK
ISIS INFLECTION POINT
U.S. STATEMENT
AQAP STATEMENT
ANTI-AL HOUTHI FORCES ATTACK
LEGEND
The data included is an open-source
collection of reported ISIS-linked
activity in Yemen, collected by
research teams at AEI’s Critical
Threats Project and the Institute for
the Study of War.
Ntrepid’s Timestream application
displays the data along a timeline,
with visual cues to represent group
affiliation and type of event.
Search terms are also highlighted in
the dataset to further show trends.

4. EMERGENCE OF ISIS IN YEMEN
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Initial reactions to ISIS in Yemen were limited geographically and in scope. There were early
pledges of allegiance to ISIS leader Abu Bakr al Baghdadi, but no indications that these
groups had developed capabilities inside Yemen.

5. ROLE OF AQAP JUDGE IN PROMOTING ISIS
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AQAP judge Mamoun bin Abdulhamid Hatem (highlighted) outwardly sympathized with ISIS
and probably facilitated an Ibb-based recruiting network. A deleted tweet from Hatem’s
account expressed support for the declaration of the Islamic Caliphate; AQAP leadership
may have ordered its deletion. An airstrike killed Hatem in al Mukalla, Hadramawt, which
was then under AQAP control, in May 2015.

6. ISIS-LINKED GROUPS ORGANIZE IN YEMEN
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The rumored ISIS-linked groups that emerged in fall 2014 began to organize into “wilayats,”
provinces, following a global ISIS organizational structure. Claims for attacks served as an
announcement for many of the wilayats, particularly Wilayat Sana’a’s March 20 attack.
There are no indications that ISIS wilayats are undertaking governance activities in Yemen.
For more, see Joshua Koontz, “Desknote: The Growing Threat of ISIS in Yemen,”
AEI’s Critical Threats Project, May 6, 2015
DECLARED ISIS WILAYAT IN YEMEN
MAR-APR MAY-PRESENTAS OF FEB
ADEN
SHABWAH
SANA’A
DHAMAR
HADRAMAWT
IBB
LAHIJ
MA’RIB
AL BAYDA

7. ISIS-LINKED ATTACKS IN YEMEN
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ISIS-linked activity is growing in Yemen, though wilayats do not appear to share capabilities.
Many attacks are claimed as independent events. Interestingly, Wilayat Shabwah claimed
participation in a local tribal offensive against the al Houthis at the end of May 2015.
current as of July 22, 2015

8. MAPPING ISIS ACTIVITY IN YEMEN
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9. ISIS EXECUTIONS IN YEMEN
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ISIS militants are publicizing their executions of al Houthis and al Houthi-aligned Yemeni
soldiers, but the casualty rate pales in comparison to ISIS executions in Iraq and Syria. ISIS
Wilayats Aden, al Bayda and Shabwah (Ataq) have participated in beheadings (highlighted),
a tactic rarely seen in the Yemeni context.

10. ISIS’S FIRST SPECTACULAR ATTACK IN YEMEN
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ISIS Wilayat Sana’a claimed credit for coordinated suicide attacks in Sana’a and Sa’ada on
March 20 that targeted mosques and was the deadliest terrorist attack in Yemen’s history.
The suicide attack in Sa’ada was disrupted. AQAP immediately denied responsibility and
cited orders from al Qaeda’s Ayman al Zawahiri not to attack mosques or market places.
For more, see Alexis Knutsen, “ISIS in Yemen: Fueling the Sectarian Fire,”
AEI’s Critical Threats Project, March 20, 2015

11. ISIS’S USE OF SUICIDE ATTACKS
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ISIS does not appear to favor suicide bombers in Yemen (attacks highlighted). Suicide attacks
have only occurred on March 20 in Sana’a and May 17 in al Bayda. ISIS may have a smaller
pool of members and potential recruits to dedicate to suicide attacks.

12. SHIFT TO ISIS VBIED ATTACKS IN YEMEN
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The first ISIS-linked vehicle-borne improvised explosive device (VBIED) attack occurred on
June 17 in Sana’a, with the near-simultaneous detonation of four bombs. Wilayats Sana’a
and Ibb are the only ISIS-linked groups in Yemen to deploy a VBIED (highlighted) to date.

13. ISIS WILAYAT SANA’A
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ISIS Wilayat Sana’a, operating in Yemen’s capital, has increased the frequency of its attacks
(highlighted) since the beginning of Ramadan. A shift from suicide attacks to improvised
explosive devices (IEDs) and VBIEDs may indicate a limited capability to field suicide
bombers.

14. ISIS WILAYAT SANA’A’S VBIED CAMPAIGN
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ISIS Wilayat Sana’a claimed VBIED attacks during the Islamic holy month of Ramadan as part
of a campaign against the “dens” of the al Houthis. The reported ISIS VBIED attack on July 2
came through a pro-ISIS Twitter account, but has not been claimed by ISIS Wilayat Sana’a.
For more, see Alexis Knutsen, “Ramadan Bombings in Yemen: Part of ISIS’s Global
Strategy?,” AEI’s Critical Threats Project, June 17, 2015

15. EVALUATING ISIS’S THREAT IN YEMEN
• ISIS wilayats in Yemen are still establishing
themselves and do not pursue governance
activities.
• ISIS’s message in Yemen does not resonate with
the population, shown by recruiting levels, and it
is not as established as AQAP there.
• ISIS’s objectives in Yemen appear to be drive
sectarian tensions in order to exploit the conflict.
• ISIS will seek to expand its foothold in Yemen as
long as the conflict continues, but its impact
remains limited to date.
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16. The data behind this report is derived from the hard work of AEI’s Critical Threats Project
Yemen Team, especially contributor Joshua Koontz who has worked tirelessly to
document ISIS and AQAP activity in Yemen, and the Institute for the Study of War. AEI’s
Critical Threats Project also partners with Praescient Analytics, whose support helped
to make this report possible, and uses Ntrepid Corporation’s Timestream, which served
as the analytical tool to derive the insights presented.
Download Timestream to view full case.
Timestream: Exploring ISIS in Yemen.tsm [37.12 MB]
Katherine Zimmerman
Critical Threats Project
American Enterprise Institute
(202) 888-6576
katherine.zimmerman@aei.org
ACKNOWLEDGEMENTS AND CONTACT INFORMATION
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