Aug. 24 (UPI) -- The United Nations' humanitarian adviser on Syria on Thursday called for an immediate humanitarian cease-fire in Raqqa to allow some 20,000 civilians to escape the besieged city.
"l cannot think of a worse place on Earth now than these five neighborhoods for these 20,000 people," Egeland said during a press briefing.
"So now is the time to think of possibilities, pauses or otherwise that might facilitate the escape of civilians, knowing that Islamic State fighters are doing their absolute best to use them as human shields," he added.
Egeland said there was heavy shelling and airstrikes taking place in the city and said there could be a large number of civilian casualties. Islamic State fighters are threatening civilians attempting to flee with snipers and arrest.
"On Raqqa, our urging today from the U.N. side to the members of the humanitarian task force ... is that they need to do whatever is possible to make it possible for people to escape Raqqa," he said.
Also on Thursday, Amnesty International said civilians are coming under fire from all sides in the battle for the city. The organization said hundreds had been killed since the offensive began to retake the city from the Islamic State in June.
"As the battle to wrest Raqqa from Islamic State intensifies, thousands of civilians are trapped in a deadly labyrinth where they are under fire from all sides. Knowing that IS use civilians as human shields, [Syrian Democratic Forces] and U.S. forces must redouble efforts to protect civilians, notably by avoiding disproportionate or indiscriminate strikes and creating safe exit routes," said Donatella Rovera, senior crisis response adviser at Amnesty International, who led the on-the-ground investigation.
Earlier this week, the Britain-based Syrian Observatory for Human Rights said U.S.-led coalition airstrikes killed at least 170 people over the previous week.
The U.S.-backed Syrian Democratic Forces militia is on the ground in Raqqa, a militant hotbed, battling the terror group. The SDF is an alliance of different ethnic groups and religions with the goal of creating a secular, democratic government in Syria.
Doctors Without Borders said last month that the ongoing battle for Raqqa has left "sick and injured civilians within and outside the city facing major difficulties obtaining urgent lifesaving medical care."
"Patients tell us large numbers of sick and wounded people are trapped inside Raqqa city with little or no access to medical care and scant chance of escaping the city," Doctors Without Borders medical coordinator Vanessa Cramond said in a statement. "In the span of a few hours on July 29, our team treated four people -- including a five-year-old -- who sustained gunshot wounds as they were fleeing Raqqa city. We are extremely concerned for the lives of those who can't get out."
The SDF surrounded and isolated Raqqa, considered the Islamic State's Syrian capital, before launching its offensive to recapture the city -- similar to what Iraqi security forces are doing in their ongoing offensive toward Tal Afar.
Andrew V. Pestano contributed to this report.