UN Urges US-Led Coalition to Rein in Airstrikes in Syria's Raqqa

"Boats on the Euphrates must not be attacked, people who come out cannot risk air raids when they come out," the Special Advisor to the United Nations Special Envoy for Syria told reporters in Geneva.

"So now is the time to think of possibilities, pauses or otherwise that might facilitate the escape of civilians, knowing that (Daesh) fighters are doing their absolute best to keep them in place," he said.

Meanwhile human right groups are warning about the consequences of US blind attacks in Raqqa.

Rights group Amnesty International on Thursday warned that the US-led coalition campaign purportedly to drive Daesh (ISIL or ISIS) out of its de-facto capital has killed hundreds of civilians, and those remaining there face greater risk as the fight intensifies in its final stages.

"As the battle to wrest Raqqa from Daesh intensifies, thousands of civilians are trapped in a deadly labyrinth where they are under fire from all sides," Amnesty Senior Crisis Response Adviser Donatella Rovera said, referring to another name used for ISIL.

"Knowing that Daesh uses civilians as human shields, SDF (Syrian Democratic Forces) and US forces must redouble efforts to protect civilians, notably by avoiding disproportionate or indiscriminate strikes and creating safe exit routes," she said.

In recent days, the US-led coalition intensified its ferocious bombing campaign in Raqqa, more than half of which has been captured by the US-led SDF battling Daesh.

Residents said on Tuesday that at least 100 civilians were killed over a 48-hour span by US-led air attacks on the city.

The UN estimates that up to 25,000 civilians may remain in the city with tens of thousands of others have already fled, risking Daesh sniper fire and mines.

The US-Led coalition earlier this month acknowledged the deaths of 624 civilians in its attacks in Syria and Iraq since 2014.

But rights groups say the actual figure is much higher, and Amnesty criticized the coalition's investigation methods for failing to include site visits or witness interviews.

"Relying on this limited methodology leads the coalition to discount a majority of reports as 'non-credible' or inconclusive, and to subsequently claim that civilian casualties account for only 0.31 percent of all engagements," the report said.

Amnesty criticized the US-led campaign for artillery and aerial bombardment on areas containing civilians and asked for an end to attacks that risk being indiscriminate.

"Whether you live or die depends on luck because you don't know where the next shell will strike, so you don't know where to run," a former Raqqa resident told Amnesty.