Iraqi forces backed by U.S.-led coalition air strikes have opened up supply lines into the town of Baiji and its nearby oil refinery, making inroads against the Islamic State militant group.
The town and refinery are located at a strategic crossroads north of Tikrit on the main Baghdad-Mosul highway.
The Pentagon on June 8 confirmed claims from the Iraqi Army over the weekend that security forces had entered the city center.
Army Colonel Steve Warren, a Defense Department spokesman, said he was not ready to declare the Baiji refinery, the country's biggest, or the town "liberated," but "progress is notable," he said.
"Friendly forces have begun moving into the town...and are methodically beginning to root out the enemy," he said.
At the refinery, Iraqi forces have broken through to troops who had been encircled by the militants and were able to deliver equipment and reinforcements.