Syrian President Bashar Al-Assad
Syrian President Bashar Al-AssadReuters

Russia will work with the United States on a response after UN investigators found that the Syrian regime had carried out chemical attacks, Moscow's UN Ambassador Vitaly Churkin said Thursday.

"We have a joint interest in discouraging such things from happening, preventing such things from happening, even in the fog of war," Churkin told reporters.

An investigative panel set up by the UN Security Council said in a report Wednesday that President Bashar al-Assad's forces had carried out at least two chemical attacks, one in 2014 and one in 2015.

It also found that Islamic State jihadists had used mustard gas in an attack on the town of Marea in northern Aleppo province in August 2015, according to the confidential report seen by AFP.

Previous reports from the Organization for the Prohibition of Chemical Weapons (OPCW), an intergovernmental watchdog, had concluded that toxic gases have been used as weapons in Syria's five-year war, but stopped short of identifying the perpetrators.

The panel of inquiry, known as the Joint Investigative Mechanism (JIM), for the first time pointed the finger of blame at the Assad regime for chemical weapons use after years of denial from Damascus.

Churkin said he spoke to his US counterpart Samantha Power on Wednesday and that they had agreed to work together to follow up on the findings.

The United States has said it will seek to ensure consequences for those responsible for the use of chemical weapons.

Chlorine use as a weapon is banned under the Chemical Weapons Convention (CWC), which Syria joined in 2013, under pressure from Russia.

Russia to study findings

Describing the new report as "very thorough," Churkin said Russian experts would carefully study its conclusions, adding that the findings were "not as simple as that."

The council is due to discuss the report on Tuesday and could decide to impose sanctions on Syria or ask the International Criminal Court to take up the matter as a war crime.

Western diplomats expect Russia, a Syrian ally, to try to shield the Damascus regime from punitive action.

Churkin, however, brushed aside suggestions that there could be confrontation at the council, saying that "it doesn't have to be the case."

The Russian ambassador described as "very important" the finding by the UN investigators of mustard gas use by IS fighters.

The panel found that the Syrian regime had dropped chemical weapons on two villages in northwestern Idlib province: Talmenes on April 21, 2014 and Sarmin on March 16, 2015.

In both instances, Syrian air force helicopters dropped "a device" on houses that was followed by the "release of a toxic substance," which in the case of Sarmin matched "the characteristics of chlorine."

The panel recommended further investigation of three other cases of suspected chemical weapons use by the Syrian regime.

There was insufficient information to reach a conclusion in the final three of the nine cases that the panel has been investigating for the past year.