The UN on Thursday called for a humanitarian pause to allow 20,000 trapped civilians to escape the besieged Syrian city of Raqqah.
"So now is the time to think of possibilities, pauses or otherwise that might facilitate the escape of civilians, knowing that Islamic State [Daesh] fighters are doing their absolute best to use them as human shields," UN humanitarian adviser on Syria, Jan Egeland, said in a news conference in Geneva on Thursday.
Noting that Daesh still held five districts in Raqqah, Egeland said: "l cannot think of a worse place on Earth now than these five neighborhoods for these 20,000 people."
He said heavy shelling and air raids were taking place and estimated a large number civilian casualties.
About upcoming Astana and Geneva peace talks, the UN deputy special envoy for Syria, Ramzy Ezzeldin Ramzy, said the talks in Kazakhstan are expected to take place in mid-September.
The Geneva talks are expected to take place after Astana, but there remains no scheduled date.
At least 78 civilians were killed in U.S.-led coalition airstrikes and Syrian Democratic Forces shelling in Daesh-held Raqqah province on Monday, according to an activist-run monitoring group, Raqqah Is Being Slaughtered Silently.
In early June, the US-led coalition launched a military campaign aimed at retaking the city, the capital of Daesh's self-proclaimed "caliphate".
Last month, the Syrian Network for Human Rights documented the death of 1,400 civilians, including 308 children and 203 women, in Raqqah in the past eight months.