1.   Islamic State of Iraq and the Levant (IS or ISIL)

Also known by its Arabic acronym Daesh, the fundamentalist Sunni Islamic organization was founded in 2004. It surged to global prominence in 2014 after announcing a self-proclaimed caliphate covering large areas of Syria and Iraq. Under the leadership of Abu Bakr al-Baghdadi, IS seeks to establish a transnational empire based on Islamic law.  The group is notorious for its brutal violence, which includes beheadings. It targets non-Sunni Muslims, as well as non-believers.

Read more about the Islamic State here. 

2.    Abu Sayyaf Group (ASG).

The Filipino jihadi organization is concentrated in the Jolo and Basilan islands, though members occasionally travel to Manila. Founded in 1991, the US has classified it as a terrorist organization since 1997. The ASG is responsible for the Philippine's worst terrorist attack in 2004: a ferry bombing that killed 116 people. Their goal is the establishment of an independent Islamic province in the predominantly Roman Catholic Philippines. They are believed to maintain loose ties to ISIL.

Read more about Abu Sayyaf here. 

3.    Harakat al-Shabab al-Mijahideen (HSM)

More commonly referred to as al-Shabab, the Salafist jihadi organization operates in East Africa, predominantly in Somalia. It has also staged attacks in Kenya. In 2006 the group held control of southern Somalia, including Mogadishu. In 2007 the area was recaptured by Somali and Ethiopian forces. Since then, HSM has retreated to rural regions, though it continues to carry out suicide bombings in urban areas. Despite infighting over leadership and a de-centralized structure, the group is thought to have between 7,000 and 9,000 members.

Read more about Al-Shabab here.

4.    Tehrik-e Taliban Pakistan (TTP)

Since 2007, the Pakistani Taliban has encompassed various militant Sunni Islamist groups in an alliance centered on the country's northwest border with Afghanistan. It is not directly affiliated with the Afghan Taliban, despite sharing the name and a primarily Pashtun ethnic composition. The TTP maintains close ties to Al Qaeda. The network orients itself against Pakistan's central government and military. Under its current leadership the group maintains a strong anti-Western ideology. Its activities include mass bombings, as well as attacks on individual targets, such as activist, Malala Yousafzi.

Read more about the Pakistani Taliban here. 

5.    Jamā’at Ahl as-Sunnah lid-Da’wah wa’l-Jihād  (commonly called Boko Haram)

Since its founding in 2002, the militant Islamist group has operated primarily in Nigeria. The name "Boko Haram" is believed to mean "Western education is a sin" in the local Hausa dialect. In recent years its activities have also crossed borders into Chad, Niger, and northern Cameroon. Boko Haram has killed at least 15,000 civilians and displaced millions of Nigerians since launching its current insurgency in 2009. The IS-affiliated group wants to overthrow the Nigerian government, which it considers to be a regime of non-believers. In April 2014, the group's kidnapping of 276 Chibok schoolgirls drew broad international condemnation.

Read more about Boko Haram here.

6.    Tahrir al-Sham (formerly Al-Nusra Front)

The former Al Qaeda affiliate has gone by a variety of monikers since its 2012 founding, including Syrian Al Qaeda, Al-Nusra Front, Jabhat al-Nusra, and Jabhat Fateh al-Sham. In July 2016, the group broke away from Al Qaeda and in January 2017, they merged with various other militant Sunni jihadi groups under their current name. Tahrir al-Sham is a key player on the rebel side in the ongoing Syrian Civil War, with the express goal of overthrowing President Bashar al-Assad.

Read more about Tahrir al-Sham here. 

7.    Hizballah or Hezbollah

With a name meaning "The Party of God," the Lebanon-based group is both a political party and a Shi'a militant Islamist organization. Certain international entities and nations, including the European Union, distinguish between Hizballah's military and political arms. The organization was founded in 1982 with Iranian financing and training as a response to Israel's invasion of southern Lebanon. The group has staged attacks against Israeli, American and Western targets. Since the outbreak of conflict in Syria, Hizballah, which supports the presidency of Al-Assad, has sent fighters to the country where they have clashed with Syrian rebel forces.

Read more about Hezbollah here.

Terror organizations - a fluctuating status

There are no universally agreed-upon criteria for what defines a terrorist organization. Different multilateral institutions, such as the United Nations and the EU, maintain their own lists, as do individual countries. This means that a militant group may a terrorist organization according to some classifications but not to others. In addition, groups may slide on or off lists depending on political situations or recent developments. For instance, the Trump administration is considering classifying the Muslim Brotherhood as a Foreign Terrorist Organization, while the recent disarmament of Colombia's FARC guerillas have spurred calls to de-classify the group as a terrorist group.

Read more about the FARC here.