Russian air strikes on the Islamic State group bastion of Raqa in northern Syria on Thursday killed at least 30 people, including 24 civilians, a monitoring group said.
The Syrian Observatory for Human Rights said they were killed and dozens of people wounded when 10 Russian raids hit the city and its outskirts.
The monitor said it had not yet confirmed how many of the remaining six people killed were civilians or IS jihadists.
The Britain-based Observatory -- which relies on a network of sources inside Syria for its information -- says it determines what planes carried out raids according to their type, location, flight patterns and the munitions involved.
Russia confirmed that six Tupolev warplanes carried out airstrikes around Raqa, but said it had demolished "a chemical weapons factory in the city's northwestern outskirts."
The defence ministry said the raids also destroyed a weapons storage facility and a training camp for IS fighters to the north and southeast.
The ministry said that the jihadists had suffered "significant material damages" in the strikes and that "a large number of fighters have been killed."
The raids comes a day after the ministry said it would halt fire around Syria's ravaged city of Aleppo for three hours each day to allow humanitarian aid in, an initiative the United Nations said is insufficient to meet the city's needs.
The UN has called for urgent aid access to Aleppo and 48-hour weekly pauses for the aid deliveries, warning that civilians are at grave risk from water shortages and disease as fighting has intensified.
Fighting between government forces and rebels in Aleppo has intensified in the past month, with both sides sending in reinforcements.