Russia is backing Syrian government claims that an alleged chemical attack earlier this year came from rebels fighting Syrian President Bashar al-Assad. Presenting evidence to the United Nations, Russian Ambassador Vitaly Churkin cited the findings of a team of Russian experts on the ground.

Vitaly Churkin: “The results of the analysis clearly indicate that the ordnance used in Khan al-Assal was not industrially manufactured and was filled with sarin. The sarin technical specifications prove that it was not industrially manufactured either. The absence of chemical stabilizers in the samples of the detected toxic agents indicate the relatively recent production. The projectile involved is not a standard one for chemical use. Hexogen utilized as an opening charge is not used in standard ammunitions. Therefore, there is every reason to believe that it was the armed opposition fighters who used the chemical weapons in Khan al-Assal.”

The Russian team was allowed in after the Syrian government blocked a U.N. investigation. Syrian rebels have blamed the government for the March attack near Aleppo, which left at least 26 people dead. The White House says it rejects Russia’s claims.