A Kurdish militia spokesman says Turkey has shelled a city in northeastern Syria as Turkish forces press into a Syrian Kurdish enclave for the fourth straight day.

Nureddine Mehmud says Turkey fired on Qamishli and other towns along the Syrian-Turkish border on Tuesday, calling it a diversion from the main campaign by Turkey and allied Syrian militia forces to invade the Kurdish enclave of Afrin, along another part of the frontier.

There were no reported casualties.

Mehmud says forces from the People's Protection Units, or YPG, have held the Turkish forces from making "any real progress" in Afrin.

The Britain-based Syrian Observatory for Human Rights Monitoring group says at 24 civilians, 24 Kurdish fighters, and 25 Turkish-backed Syrian militiamen have been killed in the clashes in Afrin since Saturday.