A child sits in an ambulance Wednesday after being pulled out of a building hit by an airstrike in Aleppo, Syria. | Aleppo Media Center via AP U.N. probe could pose new Syria dilemma for Obama

A U.N. investigative report due out as early as next week could force President Barack Obama to once again grapple with the tricky subject of chemical weapons use in Syria — including how far to push Russia at a time of escalating tensions.

The report of the "Joint Investigative Mechanism" is likely to officially attribute a number of instances of chemical weapons attacks over the past three years to the regime of Syrian President Bashar Assad, who officially gave up his stockpiles of such deadly agents in 2013. The highly anticipated report would come in the wake of a new spate of such alleged attacks in Syria.


The question for Obama and his aides will be what action to demand from the U.N. Security Council, whose members include veto-wielding Russia.

“This should be very important to President Obama because he’s so committed to looking for alternatives to military force to resolve these kinds of issues,” said Rebecca Hersman, a former deputy assistant secretary of defense for countering weapons of mass destruction.

A State Department official familiar with the issue, who noted that the contents of the JIM report remain a mystery, said that if Assad is named as a perpetrator, the Russians are likely to block any substantial effort to punish the Arab leader, whose government Moscow has militarily backed as it fights an array of rebel groups. That could further deepen the distrust between the U.S. and Russia, even as Secretary of State John Kerry tries to persuade Moscow to cooperate on other fronts to bring an end to the five-year Syrian civil war.

"The Russians will say it’s politicized. They’re going to say that what’s important is to look at non-state actors and the Islamic State and terrorists," the official predicted. In return, the U.S. will likely "seek to get them to compromise and agree to certain measures of accountability, whether it is against the regime or non-state actors or other groups." Those measures, he said, could include targeted sanctions.

Assad agreed in September 2013 to give up his chemical weapons stockpiles after mounting evidence he had used deadly agents such as sarin to kill hundreds of people, many of them civilians. Obama, who had earlier warned Assad that any use of chemical weapons would be crossing a "red line," has since pointed to the large-scale dismantling of Syria's chemical weapons program as a justification for not launching U.S. military strikes against the Arab dictator.

But since that 2013 arrangement, there have been dozens of alleged uses of chemical weapons in the Syrian conflict, most of which are thought to be the work of the regime. In recent days, a such attacks are reported to have taken place in the northern Syrian city of Aleppo, which is facing intensified fighting in the wake of a broken cease-fire.

Many of the attacks involve chlorine, a chemical that, because of its multiple legal uses, was not included as part of the 2013 deal. Still, using chlorine as a weapon — its gas form can lead to suffocation — is forbidden by the Chemical Weapons Convention, which Syria joined as part of the 2013 deal. Assad's critics note that many of the chlorine attacks involve the use of barrel bombs dropped by helicopters, which only the regime possesses.

The JIM, which is tied to the U.N.'s Organization for the Prohibition of Chemical Weapons, was set up last fall and given a one-year mandate. It is investigating seven (or nine, depending on how they are grouped) cases where the deadly chemical agents are believed to have been used. It is not a judicial body — its main purpose is to name the suspected perpetrators of the chemical weapons attacks in Syria so that the U.N. Security Council can decide what to do.

The cases being investigated, according to a fact sheet provided by the JIM, occurred between April 2014 and August 2015 in various parts of Syria, including the Aleppo and Idlib regions. The probe work includes interviews with witnesses, visits to Syria and the cooperation of forensic institutes and specialized laboratories.

On Wednesday, Syrian opposition leaders urged U.N. officials to instruct the JIM to investigate the most recent alleged chemical weapons attacks in Aleppo and other areas.

"How many more Syrians must die before the member states of this Security Council are compelled to act?" said opposition leader Riyad Hijab. "The Security Council and its member states have the mandate to protect civilians from chemical weapons attacks, it is high time they used it."

A spokeswoman for the JIM declined to comment.

Although it has a limited mandate, the JIM's mere creation was an important step for the international community, not least because it's an effort to prevent the use of chemical weapons from becoming even more normalized in theaters of war, observers said.

"This is the first time that we have sought to directly attribute the use of chemicals weapons through a legal international mechanism," said Hersman, who is now with the Center for Strategic and International Studies. "This mechanism is unprecedented. It has never existed before. We’re creating a process of legal accountability.”

Hersman also said she was struck by the latest news out of Aleppo. “It is, ironically, not surprising that we are seeing yet another instance, fairly large scale, of the use of chemical weapons ahead of the [JIM] report," she said. "There’s a strange track record of the Syrians using chemicals as weapons in this conflict even at times when you think restraint might be encouraged.”

U.S. officials and analysts both noted that it's possible that the JIM's report will be cautious in the language it uses to attribute the attacks to any perpetrators, and that it's also possible the Islamic State terrorist organization, which controls vast tracts of Syria, could be among those named.

But Stephen Rapp a former U.S. ambassador-at-large for global criminal justice, said that if the report attributes cases of chemical weapons use to Assad, it could at the very least embarrass Russia, forcing it to answer the question: "How can you possibly be engaged in joint military operations with this fellow?"

"It really undermines their position," Rapp said. "It undermines their efforts to get other countries to join with them on their side in Syria."