>> U.S.-backed forces are advancing from all sides in this Syrian city of Raqqa. Leaving Islamic state militants surrounded. Reuters correspondent, John Davison.>> Here we are just outside Raqqa old city just across the road from here the old city walls of Raqqa. We're with a unit from the YPG Kurdish group, which is part of the Syrian Democratic Forces Alliance, which is fighting against Islamic State in the center of the city.
>> He says the Syrian Kurdish commander has told him it could take up to four months to dislodge the militants from what they see as their capital.>> Some of the main challenges facing the SDF include the fact that there are many>> Civilians trapped inside the city and Islamic State are using snipers and rigged all the neighborhoods with mines.
So the advances are being very,very slow and very cautious. This is why it's taking so long to push well into the old city.>> Fighters are also being targeted by IS car bombs as they push forward.>> Up to 50,000 civilians are believed to be trapped inside the city.
The STF but by S strikes coalition special forces have been fighting since June to remove the militants. It's mostly foreign forces battling to the end. They command the same militants from the Russian region of Chechnya particularly Deathli.>> They say, the further they advance, the harder the fight.