A far-left terror suspect was arrested in northwestern Turkey while attempting to illegally cross into Greece, a security source said Monday.

The arrest took place when the suspect affiliated with the Revolutionary People's Liberation Party/Front (DHKP-C) terrorist group was spotted in a restricted military zone in the Meriç district of Edirne province.

The suspect, identified by the initials H.E., was taken to the Gendarmerie General Command, said the source, who wished to remain anonymous due to restrictions on speaking to the media.

The DHKP-C is responsible for a number of terrorist attacks in Turkey, including the assassination of business tycoon Özdemir Sabancı in 1996, and an attack on the U.S. Embassy in Ankara in 2013, which killed a Turkish security guard.

The group is listed as a terrorist organization by Turkey, the U.S. and the European Union.

It has become less active in the country in recent years but remains a major security threat.