Following a series of bomb blasts in Maiduguri, a city in northeast Nigeria, that killed a reported 54 people and injured 143 others, Nigerian militant group Boko Haram released a recording pledging official allegiance to the Islamic State group. The recording’s authenticity was confirmed Saturday by Flashpoint Intelligence, a global security firm, NBC News reported.

The voice on the recording is said to be that of Boko Haram leader Abubakar Shekau addressing Islamic State group leader Abu Bakr al-Baghdadi, and calling on Muslims throughout the world to declare a similar loyalty. The group is just the latest Islamist organization from Africa and the Middle East to do so.

According to data gathered by the Intel Center, a private company that studies terrorist groups, 31 groups have now sworn either support or allegiance to the Islamic State group.

Boko Haram has been responsible for tens of thousands of deaths and displacement of an estimated 1 million people in the past year and now controls an area about 52,000 square kilometers, roughly the size of Slovakia, according to an estimate released by The Telegraph.

The pledge follows similar messages of solidarity from Islamist militant groups in Egypt, Libya, Algeria, Yemen and Saudi Arabia in November, and militants in Afghanistan and Pakistan announced that they were forming an ISIS “province” in January.

The move is also not Boko Haram’s first affirmation of support for the so-called caliphate established by ISIS. Last June, after ISIS jihadists declared the captured areas of Iraq and Syria a caliphate, ISIS leader Abu Bakr al-Baghdadi proclaimed himself caliph and urged other radical Sunni groups to pledge their allegiance. Later in 2014, Shekau vowed support for the group and Baghdadi as well as other Islamist groups in a video statement, BBC News reported.

The Pakistani Taliban declared allegiance to Islamic State in October, noting in a message marking the Muslim holy festival of Eid al-Adha, that they fully supported ISIS’ goals, Reuters reported.

"Oh our brothers, we are proud of you in your victories. We are with you in your happiness and your sorrow," Taliban spokesman Shahidullah Shahid said in a statement sent to Reuters by email from an unknown location.

A full list of the 31 groups pledging support or allegiance to ISIS, according to Intel Center, is below:

  • al-I'tisam of the Quran and Sunnah [Sudan] -- Aug. 1, 2014 -- Support
  • Abu Sayyaf Group [Philippines] -- June 25, 2014 -- Support
  • Ansar al-Khilafah [Philippines] -- Aug. 4, 2014 -- Allegiance
  • Ansar al-Tawhid in India [India] -- Oct. 4, 2014 -- Allegiance
  • Bangsamoro Islamic Freedom Fighters (BIFF) [Phillipines] -- Aug. 13, 2014 -- Support
  • Bangsmoro Justice Movement (BJM) [Phillipines] -- Sept. 11, 2014 -- Support
  • al-Huda Battalion in Maghreb of Islam [Algeria] -- June 30, 2014 -- Allegiance
  • Heroes of Islam Brigade in Khorasan [Afghanistan] -- Sept. 30, 2014 -- Allegiance
  • The Soldiers of the Caliphate in Algeria [Algeria] -- 30 Sep. 2014 -- Allegiance
  • Jundullah [Pakistan] -- Nov. 17, 2014 -- Support
  • Islamic Movement of Uzbekistan (IMU) [Pakistan] Statement -- Sept. 24, dated Sept. 12, 2014 -- Support
  • Islamic Youth Shura Council [Libya] -- June 22, 2014 -- Support
  • Jaish al-Sahabah in the Levant [Syria] -- July 1, 2014 -- Allegiance
  • Faction of Katibat al-Imam Bukhari [Syria] -- Oct. 29, 2014 - Allegiance
  • Jamaat Ansar Bait al-Maqdis [Egypt] -- June 30, 2014 -- Allegiance
  • Jund al-Khilafah in Egypt [Egypt] -- Sept. 23, 2014 -- Allegiance
  • Liwa Ahrar al-Sunna in Baalbek [Lebanon] -- June 30, 2014 -- Allegiance
  • Islamic State Libya (Darnah) [Libya] -- Nov. 9, 2014 -- Allegiance
  • Lions of Libya [Libya] (Unconfirmed) -- Sept. 24, 2014 -- [Support/Allegiance]
  • Shura Council of Shabab al-Islam Darnah [Libya] -- Oct. 6, 2014 -- Allegiance
  • Mujahedeen Indonesia Timor (MIT) [Indonesia] -- July 1, 2014 -- Allegiance
  • Mujahedeen Shura Council in the Environs of Jerusalem (MSCJ) [Egypt] -- Oct. 1, 2014 -- Support
  • Tehreek-e-Khilafat [Pakistan] -- July 9, 2014 -- Allegiance
  • Okba Ibn Nafaa Battalion [Tunisia] -- Sept. 20 2014 -- Support
  • Mujahedeen of Yemen [Yemen] -- Nov. 10, 2014 -- Allegiance
  • Supporters for the Islamic State in Yemen [Yemen] -- Sept. 4, 2014 -- Allegiance
  • al-Tawheed Brigade in Khorasan [Afghanistan] -- Sept. 23, 2014 -- Allegiance
  • Supporters of the Islamic State in the Land of the Two Holy Mosques [Saudi Arabia] -- Dec. 2, 2014 -- Support
  • Ansar al-Islam [Iraq] -- Jan. 8, 2015 -- Allegiance
  • Leaders of the Mujahed in Khorasan (10 former TTP commanders) [Pakistan] -- Jan. 10, 2015 -- Allegiance
  • Boko Haram [Nigeria] -- March 7, 2015 -- Allegiance