The town has been besieged by Islamic State (IS) fighters for two months, with over 15,000 people trapped inside.
The mayor of the town said: “Security forces and militia fighters are inside Amerli now after breaking the siege and that will definitely relieve the suffering of residents.”
The advance follows US airstrikes around the town, and air drops of humanitarian supplies to the residents from British, French and Australian planes.
The majority of the town’s population are Turkmen Shi’ites, which the IS regards as apostates, and had armed themselves to hold off IS attacks.
One Amerli resident, Amir Ismael, said on the phone: “I can see the tanks of the Iraqi army patrolling Amerli’s street now. I’m very happy we got rid of the Islamic State terrorists who were threatening to slaughter us.”