"On August 2, a residential district was attacked with poisonous substances from the area controlled by Harakat Nour al-Din al-Zenki militants, considered by the US to be so-called 'moderate opposition'," the center's chief Lt. Gen. Sergei Chvarkov said.
As a result of this terrorist attack, seven people died and 23 were hospitalized with symptoms of suffocation and inhalation burns.
The Russian Center for Syrian reconciliation has informed the American side about the militants' attack, Chvarkov said.
Aleppo is partially controlled by Jabhat Fatah al Sham (previously known as the al-Nusra Front), a terrorist group outlawed in Russia and other countries along with Daesh.
On Tuesday, RIA Novosti reported citing popular defense forces that terrorists used chemical weapons in the city killing at least five civilians.