Turkish security forces apprehended four YPG terrorists attempting to infiltrate its cross-border operational zone in northern Syria, the National Defense Ministry said Monday.

After trying to cause disruptions in the Operation Peace Spring region, the terrorists were "neutralized," the ministry said on Twitter.

Turkish authorities use the term "neutralize" to imply the terrorists in question surrendered, were killed or were captured. The YPG is the Syrian offshoot of the PKK terrorist group.

Since 2016, Turkey has launched a trio of successful anti-terror operations across its border in northern Syria to prevent the formation of a terror corridor and to enable the peaceful settlement of residents: Euphrates Shield (2016), Olive Branch (2018) and Peace Spring (2019).

Turkey's Operation Peace Spring cleared terrorists from more than 4,300 square kilometers (1,660 square miles) in northern Syria, according to Foreign Ministry figures.

As part of two separate deals with the U.S. and Russia, Turkey paused the operation to allow the withdrawal of YPG terrorists from the planned northern Syria safe zone.

The deal with Moscow, reached on Oct. 22, specified that security forces from Turkey and Russia would mount joint patrols in the area within 30 kilometers (18.6 miles) south of Turkey's border.

Turkey has long decried the threat from terrorists east of the Euphrates in northern Syria, pledging military action to prevent the formation of a "terrorist corridor" there.

In its more than 40-year terror campaign against Turkey, the PKK – listed as a terrorist group by Turkey, the U.S., and the European Union – has been responsible for the deaths of 40,000 people, including women, children and infants.