Baghdad, AP—Iraqi soldiers battling the Islamic State of Iraq and Syria (ISIS) group recaptured the heart of the town of Baiji, home to the country’s largest oil refinery, state television and a military official said Tuesday.

Retaking Baiji, 155 miles (250 kilometers) north of Baghdad, could allow Iraqi forces a base to attack neighboring Tikrit, taken by the extremists after their lightning advance this summer. It also represents a morale boost for Iraq’s beleaguered security forces, which saw many of its troops flee the militant offensive.

State television quoted the top army commander in Baiji, Gen. Abdul Wahab Al-Saadi, as saying troops recaptured the city’s local government and police headquarters at the center of the town. It aired what appeared to be archival footage of the town showing Iraqi army troops firing their weapons from behind sand barriers.

Saadi later spoke to state television by telephone but the line appeared to be cut off after he said his forces were meeting stiff resistance.

A senior military official reached by telephone in Beiji confirmed the recapture of the city center, but added that intense clashes continued elsewhere in the town. He told The Associated Press that 75 percent of Baiji was now in the hands of government troops. He spoke on condition of anonymity because he was not authorized to speak to journalists.

Government officials in Baghdad offered no immediate comment on the reports. Saadi said Saturday that his forces had recaptured most of the city and that it would soon be entirely rid of ISIS fighters.

There was no word on the fate of the refinery, which lies on the outskirts of the town and has been besieged by ISIS fighters since June. The small army unit inside the refinery, resupplied and reinforced by air for months, successfully resisted wave after wave of extremist assaults.

Iraq’s army and security forces have partially regrouped after melting away in the face of the summer’s ISIS offensive. In recent weeks, they recaptured a string of small towns and villages, but taking Bqiji would be strategically significant in what is shaping up to be a drawn-out campaign against the extremists.

Recapturing Baiji would also be a major boost for Iraq’s Shi’ite-led government and could pave the way for a fresh offensive to drive ISIS militants from the nearby city of Tikrit, Saddam Hussein’s hometown and the capital of Salah Al-Din province.

The campaign to retake Baiji suffered a serious setback on Friday when a suicide truck bomber struck the convoy of a top Iraqi police officer, killing eight people, including the ranking official, Lt. Gen. Faisal Malik Al-Zamel. Zamel and Saadi jointly led the Baiji campaign, carried out by a contingent of troops and security forces drawn from a nearby military base and airlifted from government-controlled areas elsewhere.

Airstrikes by a US-led coalition have aided Iraqi forces, militias and Kurdish Peshmerga fighters battling ISIS militants. Hundreds of US advisers and trainers have also been working with the Iraqis.

US Central Command said Monday that coalition aircraft conducted seven airstrikes near Baiji since Friday, destroying three small militant units, a sniper position, and two militant vehicles, including one used for construction.