Syrian air strikes on the Islamic State "capital" killed dozens of civilians and may amount to war crimes, according to Amnesty International.
The human rights group said it has documented a series of Syrian government air strikes between November 11 and November 29 that killed up to 115 civilians, including 14 children, in the city of Raqqa in northern Syria.
At least 60 people were reportedly killed in air strikes on November 25 in Raqqa.
Raqqa has been the seat of Islamic State since it declared a caliphate in areas under its control in Iraq and Syria.
Amnesty said the "unlawful" killings violated international humanitarian law and some of the attacks may amount to war crimes.
The London-based group said the air strikes included attacks on a mosque and a busy market "crammed full of civilians" as well as some buildings not being used for military purposes.
Philip Luther, director of Amnesty's Middle East and North Africa programme, said: "Syrian government forces have shown flagrant disregard for the rules of war in these ruthless air strikes. Some of these attacks give every indication of being war crimes.
"They have carried out repeated attacks on civilian areas without clearly identifying military targets, a blatant violation of the requirement to distinguish between civilians and military targets."
Syrian authorities said at the time that the attacks were meant to target IS members and bases, but Amnesty said the evidence it gathered shows that, in most cases, no military targets could be identified.
On November 25, Syrian government forces bombed a number of civilian areas, striking a mosque, a busy market, shops, a transport hub, a storage facility and a residential building, Amnesty said.
Mr Luther said: "The residents of Raqqa already have to endure the reality of life under brutal IS rule. Punishing an entire civilian population simply because the city where they live is now under IS control can never be justified."