By Louis Charbonneau
UNITED NATIONS (Reuters) - War crimes in Syria's five-year-old conflict are widespread and Syrian government forces and Islamic State militants continue to commit crimes against humanity in the face of inaction by the international community, a U.N.-backed panel said on Monday.
"Flagrant violations of human rights and international humanitarian law continue unabated, aggravated by blatant impunity," the U.N. Independent International Commission of Inquiry said in its latest report.
"The stipulations of relevant Security Council resolutions ... remain largely unheeded and unimplemented," it said. "Crimes against humanity continue to be committed by government forces and by ISIS (Islamic State). War crimes are rampant."
The U.N. inquiry, composed of independent experts, has long denounced the use of starvation by both sides in the Syrian conflict as a weapon of war, and has a confidential list of suspected war criminals and military units from all sides which is kept in a U.N. safe in Geneva.
The report said that Russian-Syrian aerial bombardments had caused the displacement of tens of thousands of men, women and children.
The commission's chairman, Paulo Pinheiro, told reporters at U.N. headquarters that none of the warring parties respects international humanitarian law. He added that the commission continues to be barred from Syria.
Speaking at the same news conference, commission member Vitit Muntharborn said they were also investigating allegations of chemical weapons use by different parties to the conflict, including alleged chlorine and mustard gas attacks.
"The fractured Syrian State is on the brink of collapse," the commission said in its 31-page report. "Indiscriminate and disproportionate attacks on the civilian population must be brought to an end."
"Government forces, anti-government armed groups and terrorist organizations employ sieges and consequent starvation, denial of humanitarian access and other forms of deprivation as instruments of war to force surrender or to extract political concessions," it said.
"Civilians, who bear the brunt, serve as little more than pawns. Their suffering has been compounded by an absence of civilian protection," it added.
The commission urged the 15-nation Security Council to refer the conflict in Syria to the International Criminal Court in The Hague or an ad hoc war crimes tribunal to ensure justice. Russia and China previously blocked a Western attempt to refer the conflict to the ICC.
Syria is not an ICC member so the only way the court could take it up is with a Security Council referral.
It said that all parties should distinguish between military and civilian targets, halt indiscriminate and disproportionate attacks, end sieges and guarantee unhindered access to humanitarian aid.
A draft U.S.-Russian plan calls for a cessation of hostilities in Syria to begin on Feb. 27 but to exclude Islamic State and al-Qaeda linked Nusra Front militants, two Western diplomatic sources said on Monday.
(Reporting by Louis Charbonneau; Editing by W Simon and Alan Crosby)