US-led coalition air strikes in Raqqa province have killed at least 10 civilians, including two children according to the Syrian Observatory for Human Rights (SOHR).
The US provides air cover to the Syrian Democratic Forces (SDF), of which the YPG is a leading component.
Turkey considers the YPG as Syria's branch of the PKK, which is listed as a terrorist organisation by the EU, the US and Turkey.
The group has made advances in western Raqqa and in two other neighbourhoods in a special ground operation to recapture the province.
But, it has come at a huge cost – the death of civilians.
Coalition fighter jets have been attacking Raqqa since March. In June, the special ground operation began.
Daesh calls Raqqa province its capital in Syria and have slowed the SDF offensive by snipers and suicide car bombs.
Dramatic rise in civilian deaths
The coalition said it had "unintentionally killed" 484 civilians in both Iraq and Syria.
A statement by the international alliance said its forces "work diligently and deliberately to be precise" in their air strikes.
But observers and activists say the number is much higher.
According to SOHR, more than 700 civilians have been killed by US-led coalition air strikes in Raqqa province since March.