(ABC News) -- A United Nations report due for release Monday is expected to confirm chemical weapons have been used in Syria's civil war, but may not finger a perpetrator.
Rebels and the regime of President Bashar Assad have each accused the other of orchestrating a chemical attack in town of Ghouta on Aug. 21, which the White House and Russian government both agree occurred.
The Obama administration estimates 1,429 were killed in the incident – including hundreds of children -- and has placed the blame squarely on Syrian government use of deadly Sarin gas.
But Moscow has bitterly disagreed, maintaining Assad's opposition may be at fault for use of the lethal toxin. It is an accusation Russia has made against the rebels during prior incidents of the war.
The Map of Alleged Chemical Attacks in Syria
The UN inspectors' primary task was simply to confirm the attack occurred and if so, identify the agent used -- assigning a perpetrator was not a main goal. However, the paper will reportedly suggest that only Assad's military has the capability to carry out such a wide-scale strike.
Regardless of whether the report identifies who is to blame, Secretary General Ban Ki-Moon said Friday it will be "an overwhelming report" and that the Assad government has "committed many crimes against humanity."
"Therefore, I'm sure that there will be surely the process of accountability when everything is over," he said.
The international body estimates more than 100,000 people have died in the war, with or without chemical weapon usage.
US and Russia Reach Deal on Syria Chemical Weapons
The report comes on the heels of a tentative agreement between the U.S. and Russia on how to rid Syria of its government stockpiles of chemical weapons reached this weekend. Under the plan, Syria would have only one week to declare its stashes.
Inspectors would arrive by November and the arms could be destroyed in the country or transferred abroad for destruction.
The ambitious deal was announced Saturday after late night meetings between Secretary of State John Kerry and his Russian counterpart, Foreign Minister Sergei Lavrov.
It is considered a diplomatic win by both the White House and the Kremlin.
The Obama administration avoids a potentially embarrassing showdown with Congress over authorization for a strike against the regime, while insisting that their threat of force was why Assad became willing to cede control of his chemical ordnance.
Meanwhile Russia, a key ally of Assad, avoids a U.S. attack that could theoretically tip the scales of the conflict against his government.
Key Players in Syrian Civil War
On Saturday, President Obama praised the Russian initiative but cautioned, "if diplomacy fails, the United States remains prepared to act."
"I welcome the progress made between the United States and Russia through our talks in Geneva, which represents an important, concrete step toward the goal of moving Syria's chemical weapons under international control so that they may ultimately be destroyed," he said in a written statement. "This framework provides the opportunity for the elimination of Syrian chemical weapons in a transparent, expeditious, and verifiable manner, which could end the threat these weapons pose not only to the Syrian people but to the region and the world. The international community expects the Assad regime to live up to its public commitments."
The president added, "more work remains to be done" and "there are consequences should the Assad regime not comply with the framework agreed today."
The agreement, which will be filed in the form of a UN Security Council resolution, allows for the use of force if investigators find Syria ducking the measure. But any violations would first need to be referred back to the UNSC, where it could still be vetoed by Russia and present the specter of a unilateral strike by the United States once more.