document: The UK-based Syrian Observatory for Human Rights reported that six women and a child were among those who died in the raids on al-Heisha overnight.
  The IS-held village has been the target of a US-backed alliance of Kurdish and Arab fighters seeking to capture Raqqa.
  A coalition spokesman confirmed that it had conducted strikes in the area.
  But Col John Dorrian told the AFP news agency that "more specific information is needed to conclusively determine responsibility" for any civilian casualties.
  A coalition statement said seven strikes near the town of Ain Issa, about 14km (9 miles) west of al-Heisha, on Tuesday had engaged six IS tactical units and destroyed three fighting positions, a vehicle, and a car bomb facility.
  A spokeswoman for the Kurdish-Arab alliance, the Syria Democratic Forces (SDF), dismissed the reports of civilian casualties as "IS news".
  On Sunday, the SDF announced that it had begun a campaign to isolate and ultimately take control of Raqqa, which IS has controlled for almost three years.
  The initial report of the air strike on al-Heisha, about 40km (25 miles) north of Raqqa, came from the anti-IS activist group, Raqqa is Being Slaughtered Silently.
  It said 23 people had been killed and identified all but four of them.
  On Wednesday, the Syrian Observatory said 20 had been killed and about 30 others wounded in the attack.
  The SDF said some 200 families had fled al-Heisha. One of the residents who escaped, Saada al-Aboud, told AFP: "[IS] fighters brought heavy weapons to our village and stayed among us so that if there were strikes they would hit us."
  "They wouldn't let us leave. We had to escape by running out into the fields, with our children and old people. What else could we do? We left everything behind."
  The Syrian Observatory says at least 680 civilians, including 169 children, have been killed since coalition air strikes began in Syria two years ago.
  However, the coalition has admitted responsibility for only 55 civilian deaths in both Syria and neighbouring Iraq between August 2014 and July 2016.
  Last month, Amnesty International said some 100 civilians appeared to have been killed in three coalition air strikes in June and July 2016 around Manbij, north-west of Raqqa, during an SDF operation to drive IS militants out of the town.
summary: A US-led coalition air strike killed at least 20 civilians in a village north of so-called Islamic State's Syrian stronghold of Raqqa, activists say.