Red Cross decries worst Syria violence since Aleppo battle

War-ravaged Syria is experiencing its worst levels of violence since the battle for Aleppo late last year, the Red Cross said Thursday, warning that the onslaught was causing "intolerable levels of suffering".

The top UN humanitarian official for the Syrian crisis also voiced alarm at a surge in violence across several regions of Syria and the number of attacks on medical facilities.

"For the past two weeks, we have seen an increasingly worrying spike in military operations that correlates with high levels of civilian casualties," Marianne Gasser, the head of the International Committee of the Red Cross delegation in Syria, said in a statement.

Violence has worsened not only in places like Raqa and Deir Ezzor, where brutal battles are under way to oust the Islamic State group, but also in many so-called de-escalation areas, like Idlib, rural Hama and Eastern Ghouta.

The de-escalation zones, agreed upon during talks in the Kazakh capital Astana, contributed to a clear reduction in violence in recent months. 

But Gasser warned that "the return to violence is once again bringing intolerable levels of suffering to wide areas of the country, while at the same time decreasing access for humanitarian agencies".

"Taken together, these are the worst levels of violence since the battle for Aleppo in 2016," ICRC said. 

It pointed out that some camps around Raqa and Deir Ezzor were receiving more than 1,000 civilians every single day as men, women, children flee the bombings and battles. 

- 10 hospitals damaged -

"Humanitarian organisations are struggling to provide water, food and basic hygiene to new arrivals," ICRC warned.

Panos Moumtzis, the UN's regional humanitarian coordinator for the Syrian crisis, said he was "appalled by reports of high numbers of civilian casualties due to heavy air attacks" across the country's front lines.

"Attacks on medical facilities are depriving people in need of their right to life-saving medical care," he said in a statement.

The ICRC said that as many as 10 hospitals had been damaged across Syria over the past 10 days alone.

Robert Mardini, who heads ICRC's Near and Middle East operations, stressed that "military operations must not disregard the fate of civilians and of the vital infrastructure on which their survival depends".

"Winning by any means is not only unlawful, but also unacceptable when it comes at such human cost," he said, urging all sides fighting in Syria to "show restraint, and to abide by the basic tenets of international humanitarian law."

More than 330,000 people have been killed in Syria since the conflict began with anti-government protests in March 2011.