Suspected Russian airstrikes killed at least 36 people Sunday in the rebel-held city of Idlib in northwest Syria, rescue workers and a monitoring group in the country reported.
The British-based Syrian Observatory for Human Rights said most of those killed were fighters in the Army of Conquest rebel group fighting forces loyal to Syrian President Bashar al-Assad. But rescue workers reported that six strikes had hit a busy marketplace in the city, several government buildings and residential area.
More than 150 people were injured in the attacks, with some of the wounded transported to hospitals across the border into Turkey.
Moscow began an aerial bombardment of what it calls "terrorist" organizations on September 30, but the West and rebel movements say the attacks have focused on anti-Assad groups, not Islamic State insurgents that the United States and its allies have been bombing.
Sunday's attack came as the New York-based Human Rights Watch group accused Russian and Syrian forces of "extensive use of cluster munitions" in the Syrian war that now has gone on for nearly five years and killed more than 200,000 people.
Syria has pledged to not use indiscriminate weapons, but one rights group official, Ole Solvang, said, "Syria's promises on indiscriminate weapons ring hollow when cluster munitions keep hitting civilians in many parts of the country."