Isil and al-Qaeda: How do the two Islamist militant groups differ?
Who leads al-Qaeda and Isil? Ayman al-Zawahiri has led al-Qaeda since the death of Osama bin Laden. Abu Bakr al-Baghdadi remains leader of Isil but is believed to have recently fended off a coup.
How many fighters do they have?
According to Western intelligence services al-Qaeda is undergoing a "resurrection". Its largest force is the 20,000 fighters it has in Syria. Last year, the US military estimated there were up to 17,100 Isil fighters in Iraq and 14,000, in Syria.
What territory do they have?
At its peak the Isil "caliphate" was roughly the size of France. Al-Qaeda's affiliates control territories in numerous countries such as Somalia and Yemen.
How does their methodology differ?
Isil inspired terrorists in the West to carry out attacks whereas in recent years al-Qaeda has concentrated on backing jihadist groups in the Middle East and Africa.
How rich are they?
Several years ago, when it controlled oil fields, Isil had an annual income estimated at US$3bn. But, no more. However al-Qaeda is still estimated to have an annual income of US$300m.