ISIS is the acronym for " Islamic State in Iraq and Syria ," also known as " Islamic State of Iraq and the Levant " , or , nowadays, just as " Islamic State " ( EI) . 
Although many refer to EI as a terrorist group , this is a simplistic categorization to explain what it represents. Chuck Hagel , who was US secretary of defense until recently , said the EI was a state project with sophisticated weapons , a totalitarian ideology and abundant resources obtained through external financing . 
The group began as another of the many who opposed the regime of Bashar al- Assad in Syria, but now claims to be religious authority over all Muslims in the world and tries to impose an ultra-conservative version of Islam to several countries .