The safety of over 400,000 people in Raqqa, Syria, where US-backed Syrian opposition forces are bombing ISIS, is of "deep concern" to the UN. The offensive has resulted in "an escalating number of civilian deaths” as well as damage to vital civilian infrastructure, the organization added.

"In past weeks, civilians have been exposed to daily fighting and airstrikes which resulted in an escalating number of civilian deaths and injuries as well as damage to civilian infrastructure, including hospitals, schools, markets and water infrastructure," a Monday statement from a spokesman for UN Secretary General read.

"There are worries" about how the US-backed operation will affect civilians, Farhan Haq, deputy spokesman for the UN Secretary-General told RT.

"We have set up camps in the area that are receiving people and we are trying to make sure that all the people displaced by the fighting can be placed in camps for their safety. But we want to make sure that whatever operations are conducted, they will bear in mind that there is a huge number of civilians who are trying to flee to safety," the UN official said.

"We need to make sure that all parties abide by the basic humanitarian norms, so civilians can be spared the consequences both of the actions by Daesh [IS] and by the air strikes," he added.

On Sunday, at least eight people, including five children were reportedly killed in airstrikes on Atabaqa city, the UN said, adding that two schools were destroyed in the attack.

Last week, "dozens of people were reportedly killed and injured in airstrikes on an IDP [Internally Displaced People] camp near Albardah village, 20 kilometers west of Raqqa," the statement added.

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In other makeshift camps in Raqqa province, which host thousands of people fleeing IS violence, "four out of five people are staying in the open air without appropriate shelter." Several children reportedly died in the camps due to lack of medical care, the organization said.

Reaching those camps is described as an "ordeal" by locals who say they are fleeing the shelling by the US-led coalition in Syria.

"All the people who come have been through the same ordeal. With me and my family, I paid about 80,000. It cost us so much. There was so much suffering and there were disabled people and sick people. It was an indescribable ordeal," a civilian at the UN-funded Karamah camp in the outskirts of the embattled city of Raqqa told Ruptly.

No humanitarian support for civilians from US – SDF

On Sunday, the Kurdish-led Syrian Democratic Forces (SDF) reported major advances in their offensive to liberate Raqqa from the Islamic State (IS, formerly ISIS/ISIL) terrorist group. "All strategic ways" through which IS have been supplying their Syrian stronghold of Raqqa have now been cut, the SDF press service said, as quoted by Kurdish news agencies.

But while the US-led coalition participates militarily, there is no humanitarian support for the civilians fleeing from terrorists, the multi-ethnic but predominantly Kurdish alliance of forces say.

With support from Washington, including air strikes, the SDF launched the offensive known as Operation Euphrates Rage six months ago. At the moment, the mission to retake Raqqa from Islamic terrorists is in its fourth stage.

While the military operation is in full force, SDF fighters have been transferring civilians through secured corridors from IS occupied areas to safe zones under their control, the Kurdish news agency Hawar (ANHA) reported.

Some 70,000 refugees have reached safer areas in northern Syria, following the battles for Raqqa and Tabqa, the agency reported, saying that the displaced civilians are settled in two camps.

The camps in the town of Kerama and Ayn Issa host some 30,000 people each according to ANHA. But as the battle in the area intensifies, the number of civilians fleeing their homes increases sharply, with more than 10,000 people having been displaced in just three days late last week.

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The Syrian Democratic Council (MSD) has said it tried to warn the international community, "specifically" Washington, of the consequences of the battle for Raqqa, having asked for assistance amid a rapidly worsening humanitarian situation.

"As the Raqqa operation was nearing, we had earlier discussed this issue with many sides, specifically with the US in order to build camps and host [civilians]. We expected tens of thousands of civilians who would be escaping Raqqa. Though there were discussions and planning, to the moment there have been no practical actions," MSD co-chair Ilham Ehmed charged, as quoted by ANHA.

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None of the over a hundred humanitarian and civil organizations operating within the region secured by SDF have contributed to the Raqqa operation either, Ehmed added.

"Drinking water is hard to find, the health situation in these camps is critical. There are not enough tents or blankets," the MSD representative added, saying that "it is critical to support these people, who are liberated from terrorism with great joy."

Otherwise, some of the people who have been living under IS for months, might even "go back to the other side, to seek hostilities" and "may join terrorist groups."

Washington's assistance to Syrian anti-government forces, who are fighting Islamic terrorists in the country, has been a constant source of controversy especially during the Raqqa offensive. Damascus sees any US presence in the country illegitimate, unless coordinated with the government.

READ MORE: Western sanctions against Syria block humanitarian relief

Earlier this week, Raqqa's civil council also released a statement, calling on humanitarian organizations and the UN to help people fleeing violence in Raqqa.

"Despite our people and the world's happiness for the overwhelming victories Syrian Democratic Forces achieved, and the progress made in liberating towns and villages in Raqqa governorate from the clutches of IS gangs, they are still turning a blind eye to the repercussions of these operations where a big number of these people are forced to displace to safe regions escaping the IS terror," the statement said.