A British-based monitoring group says Syrian and Russian warplanes conducted a series of air strikes over the weekend that killed dozens of people in areas held by rebels fighting to take control of the city of Aleppo.
The Syrian Observatory for Human Rights said that air strikes on August 13-14 killed 45 civilians in and around Aleppo and 22 in the neighboring Idlib Province.
The monitoring group said the bombardments targeted areas held by the Army of Conquest, an alliance of rebel, Islamist, and jihadist forces that has mounted a major offensive in the Aleppo area.
It said heavy fighting took place in various parts of Aleppo on August 14 as rebels assaulted government-held sectors in the city's northwest and south.
Hundreds of people have been killed and many civilians deprived of vital supplies during intense fighting in recent weeks for control of Aleppo.
Russia has supported Syrian President Bashar al-Assad's government throughout the more-than-five-year war and helped him stave off potential defeat by launching a campaign of air strikes in September 2015.