The Syrian Democratic Forces' coordination and military operations centre reported "intensive bombardment by Turkish jets on military positions and civilian villages" in the areas of Ras al-Ain, Tal Abyad, Qamishli and Ain Issa.

"According to initial reports there are casualties among civilian people," it said in a statement.

The SDF also said that a total of 25 Turkish jets have been involved in the initial phase of the offensive, striking a total of 16 targets across the wide border area.

It reiterated its call on the United States and the military coalition it leads in the region to implement "a no-fly zone to stop the attacks on innocent people".