The Syrian Democratic Forces (SDF), backed by coalition aircraft, are days away from liberating the Syrian city of al-Raqa from the "Islamic State of Iraq and Syria" (ISIS), officials from the Arab-Kurd alliance tell Diyaruna.

The SDF currently holds around 90% of the city, they said.

"The liberation of the entire city of al-Raqa is expected to be announced in the coming days or by the middle of this month at the latest," SDF media official Mustafa Bali told Diyaruna.

This is contingent on operations proceeding as planned, he said, noting that ISIS has been using civilians as human shields in order to slow the SDF advance.

Battles are currently focused on the last ISIS strongholds in the city, "around the National Hospital, in al-Fardwas district, the train station and the area around the Globe square", he said.

"It would have been possible to complete the liberation operation earlier, had ISIS not exploited the presence of civilians in the city," he said.

Talks for the safe exit of civilians trapped in al-Raqa were under way Wednesday (October 11th), as the SDF prepared for its final push, AFP reported.

Safe passage for civilians

On Tuesday, the coalition said officials from al-Raqa Civil Council were trying to negotiate the safe passage of civilians from remaining ISIS-held areas.

"Al-Raqa Civil Council is leading discussions to determine the best way to enable civilians trapped by ISIS to exit the city, where some are being held as human shields," the coalition said.

"Those departing al-Raqa who are found to have fought for ISIS will be turned over to local authorities to face justice."

SDF spokeswoman Jihan Sheikh Ahmed told AFP that between 600 and 700 active ISIS fighters were believed to remain in al-Raqa, with an additional 800 to 900 wounded fighters also still inside the city.

She said some ISIS elements had tried to disguise themselves among the hundreds of civilians fleeing the city on Tuesday, while at least one had handed himself in to SDF fighters.

According to UN estimates, up to 8,000 people may still be in al-Raqa, although each day groups ranging from a dozen to several hundred people escape towards the SDF.

After al-Raqa is liberated, the SDF command will decide when displaced residents can return, Bali said, as sweep operations must be completed to ensure the city is cleared of mines and improvised explosive devices (IEDs).

'Human shields' slow advance

The military operations could have ended some time ago, SDF unit commander Ghassan Ibrahim told Diyaruna, but the general policy of the SDF and coalition commands calls for minimizing civilian casualties.

"The ISIS terrorist group is still holding thousands of citizens in the city and using them as human shields," he said.

This has slowed down the operation significantly, Ibrahim said, and means the liberating forces have had to chip away slowly at ISIS defenses, taking one street and one neighbourhood at a time.

"Meanwhile, specialised teams are removing mines and IEDs planted by the group to obstruct and impede the advance of the liberating forces," he said.

The coalition has been critical to the success of the ground operations, through precision airstrikes against ISIS positions in the city, he said, as well as by providing equipment, weapons and ammunition.

The battle for al-Raqa

The battle for al-Raqa is distinguished by the large number of ISIS elements inside the city, Ibrahim said, as fighters who were positioned in the province’s rural areas fled there under fire.

The group's networks of underground tunnels and passageways created by punching holes in the walls of adjacent buildings present an additional obstacle and must be destroyed, he added.

Al-Raqa resident Jamal al-Bakkar, 50, told Diyaruna he fled the city for Ayn Issa camp with the help of an SDF special forces unit that reached his house in the National Hospital area and evacuated him, along with other families.

"The SDF are constantly trying to communicate with the civilians who remain in the city to get them out," he said.

"Movement inside the city of al-Raqa is fraught with extreme danger," he added, as ISIS has planted mines in areas where civilians gather in order to prevent them from fleeing.

ISIS elements open fire immediately and directly at anyone who tries to leave the city, al-Bakkar said, adding that snipers are deployed in high locations overlooking the places where civilians gather.