Syrian fighters backed by US special forces battled Thursday to clear the last remaining Islamic State group jihadists holed up in their crumbling stronghold of Raqa.
"Victory is near" and would be declared in coming weeks, a spokeswoman for the operation to capture Raqa told AFP in the city where US-led air strikes sent clouds of grey smoke into the air.
Across the border in Iraq, security forces were attacking all remaining territory held by the extremists, who are fighting to prevent the all-out collapse of their self-proclaimed "caliphate".
Most of Raqa, long a byword for the jihadists' most gruesome atrocities, is now in the hands of the US-backed Syrian Democratic Forces, supported by waves of heavy air strikes by a military coalition led by Washington.
"We control 80 percent of Raqa and the other 20 percent is in the firing line of our forces," said Jihan Sheikh Ahmed, spokeswoman for the "Wrath of the Euphrates" operation.
"We're in the final stage and will deliver victory to our people in Raqa within weeks," she told AFP.
She said the Kurdish-Arab alliance was still fighting the jihadists around grain silos in the north of the city and the Raqa sports stadium, where IS fighters are believed to be storing weaponry.
"But victory is near," she said.
SDF spokesman Talal Sello said the militia was battling jihadists in "20 percent of the city".
"That sector is not under the control of Daesh... our forces are present there," he told AFP.
In the city Thursday, an AFP correspondent heard US-led coalition warplanes carrying out air strikes around the silos.
The sound of gunfire from running battles could also be heard as an AFP journalist travelled across parts of the city.
- 'Mopping up operation' -
The Britain-based Syrian Observatory for Human Rights monitor said the SDF and US special forces were engaged in a "mopping up operation."
But the operation was being slowed down by large numbers of mines planted by the jihadists in the city, where they have been under siege for three months, it said.
Exact estimates of the percentage of the city held by the SDF vary, with the Observatory putting it at 90 percent, but the US-led coalition saying that 70 percent had been "cleared."
IS seized Raqa in early 2014, making it their de facto Syria capital. They are thought to have used the city to plan attacks abroad.
Across the border in Iraq, security forces backed by paramilitary units launched a dawn assault on a besieged IS-held pocket around the northern town of Hawija, just days after attacking the jihadists' only other foothold in the country.
The territory still held by IS has been dwindling fast since its defeat in Iraq's second city Mosul in July, with stronghold after stronghold coming under assault on both sides of the border with Syria.
After the defeat of IS in Mosul and the recapture of adjacent areas, Hawija and neighbouring towns form the last enclave still held by IS in Iraq apart from a section of the Euphrates Valley downstream from the border with Syria.
"Greetings to all of our forces, who are waging several battles of liberation at the same time and who are winning victory after victory and this will be another, with the help of God," Iraqi Prime Minister Haider al-Abadi said.
- Concern for civilians -
An AFP correspondent heard heavy shelling around the IS-held town of Sharqat where Iraqi forces have been massing in recent days.
The US-led coalition fighting IS hailed the new offensive.
"Daesh is losing ground and failing in every battle. Soon ISIS will have no sanctuary in Iraq," said coalition spokesman Colonel Ryan Dillon using another acronym for IS.
Humanitarian organisations expressed concern for the fate of civilians caught up in the offensive.
"The 85,000 civilians still in and around Hawija, including around 40,000 children, now face a terrifying time as they worry about getting caught up in the fighting or being hit by an air strike," said International Rescue Committee acting country director Jason Kajer.
"For those who decide to flee, there is a significant risk of being targeted by ISIS snipers or killed by a mine."
The UN estimates up to 15,000 civilians may remain trapped in Syria's Raqa, facing "incredibly difficult conditions" including food, water and medical shortages.
IS also holds pockets of territory in Syria's eastern province of Deir Ezzor, where the extremists are facing separate offensive by Russian-backed government troops and the SDF.
In Syria they are also present in eastern parts of the central provinces of Homs and Hama and have come under attack by Russian-backed government forces there too.
In Iraq, government forces are also pursuing IS in the western desert near the border with Syria.