In Iraq this weekend, government forces against the Sunni militant group known as the Islamic State of Iraq and Syria, or ISIS. On Sunday, the it was using Russian-made jets to attack Sunni militants in the northern cities of Tikrit, the hometown of the late dictator Saddam Hussein, and Mosul. Both cities remain under insurgent control.

The battle is familiar to many U.S. veterans of the Iraq war. Ten years ago, thousands of U.S. soldiers battled Sunni fighters in the same cities.