The latest figures United Nations figures said that 1,000 children have been killed in Syria this year. The intensity of the attacks has accelerated in the past two weeks, during which about 700 civilians were reported killed.
The U.N. investigators called on Russian Federation and the U.S.to probe their actions, which they claim violated worldwide law.
The International Committee of the Red Cross (ICRC) has confirmed that it was forced to interrupt the distribution of humanitarian aid on Monday to the population of Syria's eastern Ghouta due to government raids.
Turkey yesterday announced it would establish camps in neighbouring Syria, including near the border in Idlib, to settle 170,000 people fleeing from the civil war.
No ISIS members were in the school nor using the school as a base, the report states, refuting USA -led coalition claims at that time.
The independent investigators called on all sides to allow access to besieged areas and all detainees.
Any peace deal must include justice, the report says.
The report, based on 500 confidential interviews with victims and witnesses overseas or in Syria via social media, calls on all sides in the war-torn country to allow access to areas that are under siege and to all detainees.
The war crimes investigators acknowledged there was "no evidence to indicate that the. attack deliberately targeted civilians or the Atareb market".
It condemned "the indiscriminate use of heavy weapons and aerial bombardments against civilians, and the alleged use of chemical weapons in Eastern Ghouta". It accused the government of using "poison gas".
More than 340,000 people have been killed and millions displaced in Syria since the start of the civil war in 2011 with the brutal repression of anti-government protests. Neighbouring countries and global powers have entered the conflict, backing allied forces on the ground.
US officials have been warning that Turkey's offensive against USA -backed forces in Syria would affect the fight against Islamic State group. Russian Federation joined the conflict in 2015, providing air and ground support for its allies in the Syrian government.
The "humanitarian pause" fell far short of a month-long nationwide ceasefire demanded by the UN Security Council last month.
In that case however, they stopped short of evoking war crimes.
There must be "no pardons or amnesties for those responsible for ordering or carrying out gross human rights violations and committing worldwide crimes such as war crimes, crimes against humanity or genocide".
The report found that USA -led coalition strikes on a school near Raqqa in March 2017 killed 150 residents, or about five times the toll announced by the Pentagon, which claimed that dozens of militants and not civilians had been killed.
"Information gathered by the Commission does not support the claim that 30 ISIL fighters were in the school at the time of the strike, nor that the school was otherwise being used by ISIL", it said.
Russian Federation has been a staunch ally of Syrian President Bashar Assad, helping him the tide of the bloody civil war in his favor.
"The Russian center for reconciliation will guarantee security for all militants who will decide to leave Ghouta with weapons and their families", said Yevtushenko, meanwhile urging all "leaders of armed groups of eastern Ghouta to guarantee the safe passage of civilians and allow the distribution of humanitarian aid".