Syria war: Raqqa civilians remain trapped in 'absolute hell'

Raqqa, the capital of so-called Islamic State in Syria, has been devastated by months of violence and assaults by US-led coalition forces.

As the fighting continues, the BBC's Quentin Sommerville describes an "iron-clad death trap" of a city with civilians facing snipers and minefields with no option for escape.

Up to 25,000 people, half of them children, remain trapped in "absolute hell", he says.