Kurdish-led forces in northern Syria say Turkish airstrikes have hit their bases near Jarablus, a town seized by Turkey-backed rebels earlier this week.

The Jarablus Military Council says the airstrikes Saturday on their bases in Amarneh village marked an "unprecedented and dangerous escalation" and came after Turkish artillery shelled the positions the day before.

The Britain-based Syrian Observatory for Human Rights confirmed the airstrikes. Turkish officials could not immediately be reached for comment.

The Jarablus Military Council is supported by the U.S.-backed and Kurdish-led Syria Democratic Forces. Turkey sent tanks across the border to help Syrian rebels capture Jarablus from the Islamic State group.

The incursion was partly aimed at containing Kurdish-led forces. Turkey says the Kurds must withdraw to the east of the nearby Euphrates River.