ANKARA

A Turkish military vehicle came under attack on Monday as Turkey and Russia held their 25th joint patrol in northwestern Syria, Turkey's National Defense Ministry said.

One of our vehicles was slightly damaged in the attack carried out by terrorists during the patrol along the key M4 highway of the restive Idlib province, the ministry said on Twitter.

An operation against terrorists in the region is ongoing, it added.

The M4 highway, also known as the Aleppo-Al Hasakah road, is about 30 kilometers (19 miles) from Turkey's southern border.

The terrorist group was not named in the statement, but the YPG/PKK has been active in the region.

In its more than 30-year terror campaign against Turkey, the PKK -- listed as a terrorist organization by Turkey, the US and EU -- has been responsible for the deaths of 40,000 people, including women, children, and infants. The YPG is the PKK’s Syrian offshoot.

This March, Ankara and Moscow agreed on a protocol urging parties to "cease all military actions along the line of contact in the Idlib de-escalation area."

The protocol said joint Turkish-Russian patrols would begin on March 15 along the M4 highway from the settlement of Trumba -- 2 kilometers (1.2 miles) west of Saraqib -- to the settlement of Ain al-Havr.

Idlib has long been under siege by the Bashar al-Assad regime forces and its allies, and previous cease-fires for the region were plagued by violations.

Turkey has worked to protect the local civilian population as well as rid the wider region of terrorist elements.