The US Pentagon announced that two FA-18 jets conducted an airstrike on ISIS artillery near Irbil, the northern Iraqi city where some US personnel are located.
President Barack Obama authorized the attacks to combat an extremist militant group and to protect American advisers and consular staff in the city.
The US has also carried out an airdrop of humanitarian supplies for thousands of families fleeing persecution from the militants.
US Secretary of State, John Kerry, is in Kabul and he spoke about the seriousness of the situation in Iraq.
"ISIL's campaign of terror against the innocent, including the Yazidi and Christian minorities and its grotesque targeted acts of violence show all the warning signs of genocide. For anyone who need a wakeup call, this is it."