American political commentator, Kevin Barrett says Takfiri groups come from the infiltration of the Islamic world by the West during the time of imperialism, when the British joined the Wahhabis of Saudi Arabia and used them against the Ottoman Empire which was the Islamic empire of the time.
He went on to say that the groups have been manufactured over the past couple of centuries into Takfiris like the al-Qaeda. He believes that groups like al-Qaeda have been sent by the CIA and Saudi Arabia to operate against Russians in countries like Afghanistan.
The commentator says these groups were made to divide and conquer the Muslim world and they are committing atrocities in the name of Islam to smear the reputation of the religion.
If you cannot see the embedded video (over 20 minutes of ranting, you can see it at the link.
*In Islamic law, takfir or takfeer refers to the practice of excommunication, one Muslim declaring another Muslim an unbeliever or kafir (pl. kuffār).