GENEVA/DAMASCUS/BEIRUT: A member of the U.N. Commission of Inquiry on Syria said Sunday she was quitting because a lack of political backing from the U.N. Security Council had made the job impossible, Swiss national news agency SDA reported.

“What we have seen here in Syria, I never saw that in Rwanda, or in former Yugoslavia, in the Balkans. It is really a big tragedy,” Carla del Ponte said. “Unfortunately we have no tribunal.”

Del Ponte, 70, who prosecuted war crimes in Rwanda and former Yugoslavia, told a panel discussion on the sidelines of the Locarno Film Festival that she had already prepared her letter of resignation.

“I am quitting this commission, which is not backed by any political will,” she said, adding that her role was just an “alibi.”

“I have no power as long as the Security Council does nothing,” she said. “We are powerless, there is no justice for Syria.”

Del Ponte, a former Swiss attorney general, joined the three-member Syria inquiry in September 2012, chronicling incidents such as chemical weapons attacks, a genocide against Iraq’s Yazidi population, siege tactics and the bombing of aid convoys.

The U.N. Commission of Inquiry said in a statement that Del Ponte had informed colleagues in June of her decision to leave in the near future. It said the investigations would continue.

“It is our obligation to persist in its work on behalf of the countless number of Syrian victims of the worst human rights violations and international crimes known to humanity,” it said.

The commission was set up in August 2011 and has regularly reported on human rights violations, but its pleas to observe international law have largely fallen on deaf ears.

Although the United Nations is setting up a new body to prepare prosecutions, there is no sign of any court being established to try war crimes committed in the 6-1/2-year-old war, nor of any intention by the U.N. Security Council to refer the situation to the International Criminal Court in the Hague.Meanwhile on the ground, Syrian state media and the Britain-based Syrian Observatory for Human Rights activist group reported pro-government forces advanced against Daesh (ISIS) in the country’s north and center, drawing closer to the key battleground of Deir al-Zor.

The Observatory said 30 Daesh militants were killed in the last 24 hours of battle for the town of Sukhneh, in energy-rich Homs province, before it was captured Saturday by pro-government forces with Russian air support.

The Syria army had also made “significant progress” south of Raqqa city, the Observatory said. “There is now just 4 kilometers between regime forces and the town of Madan, which is the last town controlled by [Daesh] in the Raqqa countryside,” the Observatory said.