At least six children have been killed and 25 wounded after a rocket hit a pre-school in the Syrian capital, Damascus.
The activist-run Unified Medical Bureau of Eastern Ghouta reported the death toll and said medical facilities in the suburb of Harista received tens of wounded children and adults following shelling on the opposition-controlled suburb.
The locally-run Education Directorate said government forces struck the school during the first break of the day.
The Britain-based Syrian Observatory for Human Rights, which relies on a network of local activists, also blamed government forces for the strike.
Earlier US-backed Kurdish-led Syrian forces announced the start of a campaign to retake Raqqa, the de facto capital of so-called Islamic State.
The announcement by the Syria Democratic Forces (SDF) at a press conference in Ein Issa, north of Raqqa, comes more than two weeks after US-backed Iraqi forces began a campaign to clear so-called Islamic State militants from their stronghold in Mosul, Iraq.
The SDF is dominated by the main Syrian Kurdish fighting force known as the People's Protection Units, or YPG.
The US considers the Syrian Kurdish fighters as the most effective force against so-called Islamic State, but Turkey views them as a terror organisation and has said it will not accept a role for the Kurds in the liberation of Raqqa.