UN investigators say they are prepared to publish secret lists of alleged war criminals in Syria to help check an "exponential rise" in atrocities from over three years of war.

Releasing the lists would put "alleged perpetrators on notice" and could "serve to maximise the potential deterrent effect" and "help to protect people at risk of abuse", a commission of inquiry said in a new report on Friday.

The commission has drawn up four lists of individuals and groups it believes are guilty of war crimes and crimes against humanity, and has kept them locked up in a safe in Geneva, Switzerland, out of concern for due process.

But the investigators said they were ready to shift their approach.

"We are trying to convince, to mobilise the international community to consider all options on the table for accountability and not to ignore the horrific, the abominable situation of the victims of this war," Paolo Pinheiro, who heads the panel, said at the UN headquarters in New York.

Asked about the report, Bashar al-Jaafari, Syria's ambassador to the UN, dismissed the inquiry as "propaganda" aimed at demonising his government.

Perpetrators identified

The investigators are set to hand over a fifth list of suspected war criminals to the UN Human Rights Council in Geneva next month, and Pinheiro said he expects a decision during the March 17 meeting on the release of the names.

"Not to publish the names at this juncture of the investigation would be to reinforce the impunity that the commission was mandated to combat," the commission said in its report.

The lists include a number of unit commanders and armed group leaders who were identified as perpetrators on the basis of their command responsibility.

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Investigators have refused to say whether Syrian President Bashar al-Assad or any of his close aides are on the list, but Navi Pillay, former UN rights chief, who was safeguarding the list, said more than a year ago that "the evidence indicates responsibility at the highest level of government, including the head of state".

The report detailed a horrifying array of crimes against humanity and war crimes committed by the Syrian regime, Islamic State of Iraq and the Levant (ISIL) fighters and other armed opposition groups.

Children are "being used as killers, as executioners and as assassins through suicide bombings. These appalling practises must be stopped", Vitit Muntarbhorn, one of the four UN commission members, said.

The commission has never actually gained access to Syria, though it has collected thousands of witness accounts, satellite photographs and documents to build up its case of human rights violations.

Meanwhile in New York, the investigators once again urged the Security Council to refer Syria to the International Criminal Court, but also suggested that the cases could go before an ad hoc tribunal similar to the one created for the former Yugoslavia.

Source: AFP