The report, from the UN Human Rights Council, found that US forces failed to take all "feasible precautions to protect civilians and civilian objects" when attacking alleged terrorists and destroying part of a mosque complex in al-Jinah, Aleppo in March 2017, in what it said were violation of international humanitarian law.
It said investigations are ongoing into "allegations that international coalition airstrikes, carried out as part of the on-going offensive to repel IS from Raqqa, resulted, and continue to result, in increasingly alarming numbers of civilians casualties."
"The Commission is gravely concerned that this offensive has led to the internal displacement of some 190,000 persons, with the fate of some 20,000 others precarious as they remain trapped in ar-Raqqah city, many of them civilians that ISIL reportedly forced to concentrate in areas under its control."
Paulo Sergio Pinheiro, Chair of the UN Commission of Inquiry on Syria, said: "We continue to investigate additional allegations that international coalition airstrikes carry out as part of the ongoing offensive to repel ISIL (Islamic State group) from Raqqa resulting in increasing number of civilians casualties."
"While looking into allegations of several such incidents, protection concerns continue to arise when commission personnel interview victims and witnesses from Al-Raqqa."
Chemical attack confirmed
The report also states that Syrian Government forces continued to deliberately target civilians, including through the use of chemical weapons against civilians in opposition-held areas including Khan Shaykhun in Idlib on 4th April.
Paulo Pinheiro says the inquiry gathered evidence, including 43 interviews with victims, eyewitnesses, first responders, and medical staff who visited the site as well as photos of remnants and satellite imaginary.
"On the basis of this information" he said, "we concluded that a chemical attack was carried out by a Syrian SU-22 aircraft which dropped 3 conventional bombs and sarin bomb in Khan Shaykhun. This sarin attack killed over 80 individuals, most of them women and children and injured hundreds of others."
'Realities of the conflict'
Meanwhile Syria's opposition must accept that it has not won the country's civil war, the UN envoy said Tuesday, voicing hope that the realities of the conflict could help forge a peace deal.
United Nations mediator Staffan de Mistura also stressed that the Syrian government cannot "simply announce victory" as such a call would be hollow without a negotiated settlement to end the six year conflict.
"The only answer is a political process", said de Mistura, who has led sputtering UN-backed peace talks, told reporters in Geneva.
In the run up to the next round of negotiations, tentatively scheduled to take place in the Swiss city next month, de Mistura has pushed the still-fractured opposition to form a single delegation that can meet face-to-face with the Damascus regime.
"Will the opposition be able to be unified and realistic enough to realise they didn't win the war?" de Mistura said.
The main opposition camp, the Saudi-backed High Negotiations Committee (HNC), has insisted that Syrian President Bashar al-Assad must leave office as part of any peace deal.
That hardline stance has put the HNC at odds with two more moderate opposition groups, known as the Moscow and Cairo platforms.
Pressure stepped up
De Mistura has in recent weeks upped the pressure on the groups to unite and said he believed they would be meeting again in Riyadh in the coming weeks, after talks there last month failed to produce a compromise.
With Islamic State jihadists facing possibly imminent defeat in the key Syrian locations of Deir Ezzor and Raqa, de Mistura raised the prospect of hosting negotiations with Syria relatively free of active fighting.
That would also require an urgently needed "national ceasefire" among the government and various rebels groups, he said.
Arab and Kurdish fighters with the US-backed Syrian Democratic Forces (SDF), as they prepare to move to the front line to battle against IS in Raqqa, Source: AAP
The UN has helped broker multiple previous truces during the war that has claimed more than 330,000 lives since 2011, but none have proved lasting.
