The following is a list of the world's top terror groups:
Islamic State, Isil or Isis: (Islamic State of Iraq and the Levant/Syria), operates across northern Iraq and Western Syria. It has its own government. Its founder is Abu Bakr al-Baghdadi.
Al-Qa'ida: The fundamentalist Islamic group was set up by Osama Bin Laden in 1989. It was responsible for 9/11, sparking off the Afghan war. When Bin Laden was killed, in 2012, Ayman al-Zawahiri took over. The group has thousands of members with military training.
Taliban: The militant extremists ran Afghanistan between 1996 to 2001. They are strict followers of Sharia law. They were overthrown by the US invasion and are supported by al-Qa'ida.
Tehrik-i-Taliban Pakistan: They operate in Pakistan's tribal regions on the Pakistan-Afghan border, and comprises several Islamist militant groups.
Boko Haram: Translated as 'western education is a sin', they abducted hundreds of schoolgirls and now has embarked on a series of massacres. This Nigerian terror group has singled itself out for its acts of barbarism.
Hamas: This is a socio-political terrorist group of Palestine, which was founded in 1987 as an offshoot of the Muslim Brotherhood. It was formed to carry out jihad against Israel, and to secure the freedom of Palestine from Israeli 'occupation'.
Farc: This Marxist-Leninist terrorist group of Colombia is considered to be the kingpin of illegal drug trade across the world.
Hezbollah: Backed up by Iran and Syria, this Lebanese terror group emerged from the Lebanese civil war of 1982. It is the biggest foe of Israel and Sunni Arab countries. It is also involved in humanitarian and social activities within the country.
Al-Nusra Front: The al-Nusra Front, or Jabhat al-Nusra, which means "The Support Front for the People of Al-Sham" in Arabic, is a branch of al-Qa'ida operating in Syria and Lebanon.
It is the strongest supporter of Syrian rebels opposing President Assad.