Turkey concerned as Syrian Kurds press toward IS-held Raqqa

This frame grab from video provided by Qasioun a Syrian opposition media outlet, shows smoke rising as a result of clashes between U.S.-backed forces and the Islamic State group, near Ein Issa, north of Raqqa, Syria. Backed by U.S. airstrikes, Kurdish-led Syrian fighters clashed on Monday with Islamic State militants north of the city of Raqqa in Syria as they pushed ahead in their offensive aiming to liberate the city that has been the de facto capital of the extremist group since 2014. (Qasioun a Syrian Opposition Media Outlet, via AP) (The Associated Press)

This frame grab from a video provided by Qasioun a Syrian opposition media outlet, shows U.S.-backed Syrian Democratic Forces fighters stationed near Ein Issa, north of Raqqa, Syria. Backed by U.S. airstrikes, Kurdish-led Syrian fighters clashed on Monday with Islamic State militants north of the city of Raqqa in Syria as they pushed ahead in their offensive aiming to liberate the city that has been the de facto capital of the extremist group since 2014. (Qasioun a Syrian Opposition Media Outlet, via AP) (The Associated Press)

This frame grab from video provided by Qasioun a Syrian opposition media outlet, shows U.S.-backed fighters taking a rest during fighting with the Islamic State group near Ein Issa, north of Raqqa, Syria. Backed by U.S. airstrikes, Kurdish-led Syrian fighters clashed on Monday with Islamic State militants north of the city of Raqqa in Syria as they pushed ahead in their offensive aiming to liberate the city that has been the de facto capital of the extremist group since 2014. (Qasioun a Syrian Opposition Media Outlet, via AP) (The Associated Press)

Turkey's foreign minister says the United States has promised Ankara that U.S.-backed Syrian Kurdish forces will only be involved in a siege of the Islamic State stronghold of Raqqa but would not enter the city itself.

Mevlut Cavusoglu said Tuesday he hopes the U.S. would keep that promise. However, he says Washington had also pledged earlier that Syrian Kurdish fighters would withdraw from the town of Manbij, which has not happened.

He says Turkey prefers that "local" Arab forces enter Raqqa, backed by U.S.-led coalition and possibly including Turkish ground troops.

The remarks reflect Ankara's concerns over the expanding ground Kurdish fighters have gained in Syria as they battle IS militants. Turkey considers the Syrian Kurdish militia be a terror organization, saying it's an extension of Turkey's outlawed Kurdish rebels.