The Islamic State militant group that has taken over large parts of Syria and Iraq and declared a self-styled caliphate poses one of the most significant threats to stability in the Middle East in years. But what danger does it immediately pose?
Here are some questions and answers about the Islamic State group:
DOES THE ISLAMIC STATE GROUP RUN A DE FACTO COUNTRY?
The Islamic State group holds roughly a third of Iraq and Syria, including several strategically important cities like Fallujah and Mosul in Iraq and Raqqa in Syria. It rules over a population of several million people with its strict interpretation of Islamic law. It also controls many of the roads linking the communities it has conquered - although much of the territory in between is sparsely populated desert.
It claims thousands of heavily armed fighters, and has set up its own civil administrations and judiciaries.
''It acts as a state in areas that don't have a state at the moment. It's effective because it provides services, it has a military presence, it speaks as a state,'' said Hassan Hassan, an analyst at The Delma Institute in Abu Dhabi.
In propaganda videos, the group lays out ambitious expansion plans that include targets such as Baghdad, Damascus and Islam's holiest city of Mecca, Saudi Arabia.
WHAT RESOURCES DOES THE ISLAMIC STATE GROUP HAVE?
The Islamic State group controls oil fields, power plants, dams and factories in Iraq and Syria. Charles Lister, an analyst who closely tracks jihadist groups at the Brookings Doha Center in Qatar, estimates the group is capable of bringing in some $2 million a day just from the sale of oil. The group has long generated cash too from extortion, kidnapping for ransom, illicit businesses and other gangland-style criminal activity.
Militarily, the group has seized heavy weaponry, including tanks, artillery pieces and surface-to-surface missiles, from Iraqi and Syrian forces. Human Rights Watch has accused the group of using ground-fired cluster munitions in at least one place in northern Syria.
WHAT DANGER DOES HAVING THE ISLAMIC STATE GROUP HOLDING THIS TERRITORY IN THE ARAB WORLD POSE?
The world has seen the risk of allowing a state sympathetic to Islamic extremists exist before. Al-Qaida was able to flourish and plot the Sept. 11, 2001 attacks in large part because it had a safe haven in Taliban-controlled Afghanistan.
The Islamic State group is a far superior threat today than al-Qaida was in 2001. It is richer, operates