The Syrian Observatory for Human Rights (SOHR) warned that the number of victims was increasing due to bombardments by the US-led international coalition, which killed 24 people, including five minors and three women, reports Efe news.

The SOHR said those who died on Saturday included 15 people who were inside an internet cafe, and among them was an NGO activist.

The ground offensive against al-Raqqa, the main IS stronghold in Syria, began last week, under the command of the Kurdish-led Syrian Democratic Forces.

The number of civilians remaining inside al-Raqqa, which before the beginning of the conflict in Syria had more than 200,000 inhabitants, is not known for certain, according to official statistics.