BAGHDAD: Iraq’s army declared victory over Daesh (ISIS) fighters in a provincial capital west of Baghdad Sunday, the first major triumph for the U.S.-trained force since it collapsed in the face of an assault by the militants 18 months ago.

The capture of Ramadi, capital of mainly Sunni Anbar province in the Euphrates River valley west of the capital, deprives Daesh militants of their biggest prize of 2015.

The fighters seized it in May after government troops fled in a defeat which prompted Washington to take a hard look at strategy in its ongoing air war against the militants.

An American defense official, speaking on condition of anonymity, said the U.S.-led campaign against Daesh was unable to confirm at this point whether the militants had been cleared out of the government complex.

After encircling the city for weeks, the Iraqi military launched a campaign to retake it last week, and made a final push to seize the central administration complex Sunday.

“By controlling the complex this means that we have defeated them in Ramadi,” said Sabah al-Numani, a spokesman for the force leading the fight on the government side. “The next step is to clear pockets that could exist here or there in the city.”

State television broadcast footage of troops, Humvee vehicles and tanks advancing through Ramadi streets amid piles of rubble and collapsed houses. Some districts appeared to have been completely destroyed by the advance.

Television also showed nighttime celebrations in mainly Shiite cities south of Baghdad for the victory in Anbar, with people dancing in the streets and waving Iraqi flags from cars.

Officials did not give any immediate death tolls for the battle. The government says most civilians were able to evacuate before it launched its assault.

Anbar provincial council member Falih al-Essawi called on the government to restore services to Ramadi quickly and start rebuilding the city to allow for the return of the displaced.

A U.S.-led coalition is waging an air campaign against Daesh but rebuilding the Iraqi army to the point that it could recapture and hold territory has been one of the biggest challenges.

In previous battles, including the recapture of former dictator Saddam Hussein’s home city Tirkit in April, the Iraqi government relied on Iran-backed Shiite militias for ground fighting, with its own army mainly in a supporting role.

Ramadi was the first major city recaptured by the army itself, without relying on the militias, who were kept off the battlefield to avoid sectarian tension with the mainly Sunni population.

The government, led by Prime Minister Haider al-Abadi, said Ramadi would be handed over to local police and a Sunni tribal force once it was secured, a measure meant to win over the community to the fight against Daesh.

“We have trained hundreds of tribal fighters, their role will be holding the ground,” said Brig.-Gen. Yahya Rasool, spokesman for the joint operations command.

The strategy echoes the “Awakening” campaign fought by U.S. forces in 2006-2007 against a precursor of Daesh, when Washington also relied on winning over local Sunni tribes and arming them to fight militants. Anbar province, including Ramadi, was one of the main battlefields during that campaign at the height of the 2003-11 U.S. Iraq war.

The government said the next target after Ramadi will be the northern city of Mosul, by far the largest population center controlled by Daesh in either Iraq or Syria.