Basis for measures taken by coalition against ISIS according to law of the armed conflicts

Islamic state of Iraq and Syria or ISIS, is a political and military terrorist organization which has been hitting the headlines since 2014. This group which has a large domination over Iraq and Syria, announced a caliphate of an Islamic state in 29th of June 2014, led by Abou Bakr Albaghdadi, chosen Raqqa as its capital. Since then, and after it began imposing its strict and widespread measures in occupied areas and also with its constant attacks and progress toward different cities in Iraq and Syria and following international community's response against this terrorist group, including the security council, a coalition led by US was formed in order to fight against ISIS. Today, in the second year of its activities, analyzing the nature of the conflict in Iraq after arrival of the coalition forces and the legal basis of their presence is mandatory. The result of this study indicates that formation of the coalition is not against international law.