(CNN) US-backed forces fighting ISIS in Raqqa say "major military operations" in the city have ended and that the jihadists have lost control of their self-declared capital.
The development marks a decisive victory in the fight against ISIS, though US officials said there were still pockets of resistance in the city.
"Major military operations in Raqqa are finished but they are now clearing the city of sleeper cells -- if they exist -- and mines," Talal Salo, spokesman for the US-backed Syrian Democratic Forces, told CNN. The SDF is a coalition of Arab and Kurdish fighters.
"The situation in Raqqa is under control and soon there will be an official statement declaring the liberation of the city."
The defeat of ISIS in Raqqa is a symbol of the terror group's decline -- it now controls a small strip of territory along the Euphrates river in northern Syria.
The city became the de facto capital of the terror group's self-proclaimed "caliphate" following a sweep of territorial gains in Iraq and Syria in 2014.
Foreign fighters swelled the ranks of ISIS in Raqqa, which it used as a base to launch terror attacks around the world.
A sustained effort to retake the city began in early June, in an operation led by the SDF and backed up by coalition air strikes. The SDF announced the final phase of the operation at the weekend.
In the past few days, the SDF said it had cleared ISIS fighters from the National Raqqa Hospital and Paradise Square, the infamous area in the center where ISIS jihadists carried out public beheadings and crucifixions.
The terror group's black flag was hauled down from Raqqa's stadium, its last hideout in the city, on Tuesday, Reuters reported.
"The SDF have taken casualties in the past hours and we expect there will still be pockets of ISIS fighters in the coming days," coalition spokesman Col. Ryan Dillon told CNN.
In a sign that the SDF operation was nearing a conclusion, coalition air strikes had eased off in the past week. There was only one US airstrike in Syria Monday, but that was far from Raqqa. Dillon said the SDF hadn't asked for air support in the past couple of days.
Raqqa Is Being Slaughtered Silently (RBSS), the award-winning network of citizen journalists who remained in the city throughout the occupation, tweeted Monday that 30 buses and 10 trucks were used to transfer ISIS fighters from Raqqa.
The group also said that since the US-backed operation to free Raqqa began in early June, there had been 3,829 airstrikes on the city, 90 suicide bombings and 1,873 victims. It said 450,000 people had been displaced.
"We don't consider it a liberation because SDF has committed many human rights violations against civilians," Abdalaziz Alhamza, co-founder of RBSS told CNN.
"Most of Raqqa people, including us, were looking forward to the day that ISIS would be defeated, but not in this scenario, having a new leadership that committed many human rights violations," he said.
Alhamza also warned that the ISIS ideology was still spreading. "They might disappear from Syria and Iraq but they will appear somewhere else," he said, adding that many will probably have returned to their families in the countryside.
Meanwhile Save the Children warned that the humanitarian crisis was escalating, despite the retreat of ISIS in the region. "The military offensive in Raqqa may be coming to an end, but the humanitarian crisis is greater than ever," the aid group's Syria director Sonia Khush said in a statement.
It warned that some 270,000 people who had fled the fighting in Raqqa still needed help, and that refugee camps were "bursting at the seams."
It said that most families had no homes to return to and that thousands of civilians were displaced in the eastern Deir Ezzor province, where fighting was still ongoing Tuesday.
"Many are plagued by nightmares from witnessing horrific violence and will need extensive psychological support," Save the Children said.