Russian airstrikes late Tuesday have destroyed the central weapons depot of a U.S.-trained rebel group, according to its commander. The Liwa Suqour al-Jabalpur rebel group, which opposes Syria President Bashar Assad's authoritarian regime, was trained by the CIA at training camps in Saudi Arabia and Qatar.

The most recent damage suffered by the group was when Russian missiles hit its main weapons depot on the outskirts of western Aleppo, according to a Reuters report. "These were considered the principal depots of the Liwa," said Hassan Haj Ali, a commander in the Liwa Suqour al-Jabalpur rebel group, to Reuters. The group was first hit when Russian warplanes began targeting rebel groups in the Syrian region of Homs last week, destroying homes and infrastructure. 

The rebel group operates in areas of western and northern Syria, where the Islamic State group -- also known as ISIS or ISIL -- has no significant presence, and where Russian jets have been bombing targets in recent days. Its weapons cache, which consisted of guided anti-tank missiles provided by countries opposing Assad, had been swinging the conflict in favor of Syria's opposition groups. However, an influx of Russian weapons throughout September had significantly helped government troops regain their grip on the battlefield and make gains in the west of the country. 

When Russia began its airstrikes last week, it claimed to be targeting ISIS-held areas, only for its first attack to be on a Free Syrian Army stronghold. U.S. Secretary of Defense Ashton Carter said that Russian airstrikes in Syria were like “pouring gasoline on the fire,” as he rebuked Moscow for its involvement in the Syria crisis and for targeting non-ISIS regions.

His comments came just hours after Russia began its bombing raids in support of Assad’s regime. “It does appear that they were in areas where there probably were not ISIL forces, and that is precisely one of the problems with this whole approach,” Carter said.