ISTANBUL — Turkey’s president said Sunday the country will launch a military assault on a Kurdish enclave in northern Syria ‘‘in the coming days’’ and urged the United States to support its efforts.

President Recep Tayyip Erdogan said the operation against the Afrin enclave aims to ‘‘purge terror’’ from his country’s southern border.

Afrin is controlled by a Syrian Kurdish militia known as the YPG. Turkey considers the YPG to be a terrorist group linked to the outlawed Kurdistan Workers’ Party (PKK) that has waged a bloody insurgency within its borders.

A YPG spokesman in Afrin said clashes erupted after midnight between his unit and Turkish troops near the border with Turkey. Rojhat Roj said the shelling of areas in Afrin district, in Aleppo province, killed one YPG fighter and injured a couple of civilians on Sunday.

Turkey and its Western allies, including the United States, consider the PKK a terrorist organization.

But the United States has been arming some of Syria’s Kurds to defeat the Islamic State group in Syria, a sore point in already tense US-Turkish relations.

Also Sunday, Erdogan’s spokesman responded to reports the US-led coalition would establish a 30,000-strong border security force in Syria involving the Kurdish militia as ‘‘worrying.’’

In December, the Associated Press reported that the United States was developing an expanded training program for Kurdish and Arab border guards in Syria to prevent the resurgence of ISIS.