They call themselves the Islamic State of Iraq and the Levant, or ISIS. They also are called IS and ISIL. Critics call them Daesh, a word Islamic State does not prefer to be called.
Islamic State has been active in Iraq and Syria since 2013. They say they follow a fundamentalist or extreme form of Islam. That fundamentalism is in response to a liberal way of life in the West, they say.
They are known for mass killings, kidnappings and beheadings of local people as well as Westerners. They have set people on fire alive and blown others up. They have crucified others.
Earlier this month, ISIS claimed responsibility for bombing a Russian passenger plane in Egypt. All 224 people on the plane were killed.
Last week, it claimed responsibility for two explosions in the Lebanese capital, Beirut. At least 41 people were killed.
And the group said it carried out attacks in Paris on Friday. More than 130 people were killed.
Experts and eye-witnesses describe their brutality as the worse ever seen.
The group was formed after U.S. forces invaded Iraq in 2003. A militant leader from Jordan named Abu Musab al-Zarqawi joined the terrorist group al-Qaida. They called themselves “al-Qaida in Iraq.”
But Zarqawi was killed in a U.S. airstrike in 2003.
Abu Bakr al-Baghdadi has led ISIS since 2010. He had been a prisoner of U.S. forces in Iraq. He and other prisoners joined IS after they were released. Other members of Islamic State come from the political party that supported Iraqi dictator Saddam Hussein. He was ousted and later executed.
In 2013, Islamic State expanded into the civil war in Syria. By June 2014, IS took control of many cities and towns in Iraq and Syria. It announced it had created a “caliphate,” or a political-religious government for Muslims.
All Muslims must reject the governments of any other country. It says other governments are signs of opposition to Islam, the religion of Muslims.
After the caliphate was announced, Islamic State called al-Baghdadi the “leader for Muslims everywhere.” This angered most Muslims who did not agree with Islamic State.
Analysts say Islamic State earns money through the illegal sale of oil in Syria, and by kidnappings, extortion and other crimes. It also receives money from supporters in some Persian Gulf nations.
U.S. government officials estimate that Islamic State may have earned as much as $100 million in 2014 from the sale of oil. The U.S. Treasury Department says the group sold the oil to local businessmen. It says they illegally transported it to Turkey and Iran, or sold it to the Syrian government.
Experts say air strikes on oil fields and refineries have reduced Islamic State earnings.
Islamic State follows an extreme version of Sunni Islam, analysts say. They are the only true believers of Islam, they say, and believe others seek to destroy Islam. This justifies why they attack Muslims and non-Muslims.
The Islamic State has also forced women into sexual slavery. It says its holy book -- the Quran -- supports the enslavement of women and girls.
Experts believe more than 3,000 Yazidi women are held by Islamic State. Some Yazidi women have escaped or were rescued. They say they were traded among fighters and given to Islamic State leaders as rewards.
Islamic State uses social media to lure young people to support its goals and join the group as fighters.
Words in This Story
caliphate – n. a political-religious Muslim government or state
refinery – n. a place where the unwanted substances in oil are removed
believer – n. someone who regards the existence of God as a fact; someone who has religious beliefs
crucify – v. to kill (someone) by nailing or tying his or her hands and feet to a cross
reward – n. something that is given for something that has been done, or that is offered for something that might be done