Turkey has long fought Kurdish insurgents within its borders, and the country now faces a severe jihadist threat in part due to Ankara's reckless policy of allowing jihadists to exploit its border with Syria. Yet it's a little-known far-left terrorist outfit that has recently emerged as Turkey's most active terror threat, and nobody seems to have noticed.
The Revolutionary People's Liberation Party/Front, or DHKP/C, is a Marxist-Leninist organization that seeks to spark a communist revolution in Turkey. Founded in 1994, its roots date back to the radical leftist movements of the 1970s. In its various forms, the group has targeted high-level Turkish political and military figures.
DHKP/C and its predecessors have assassinated former Prime Minister Nihat Erim (1980), army Gen. Temel Cingöz (1991) and Israeli Consul-General Efraim Elrom (1971), among others. Listed as a terrorist group by the U.S. and the European Union, the DHKP/C is strongly anti-American and anti-NATO. It believes Turkey's government is controlled by Western powers and seeks to break those bonds, especially with NATO.
While it went quiet in the mid-2000s—the group's founding leader, Dursun Karataş, died from cancer in 2008—the DHKP/C has made a remarkable comeback since 2012. It appears to have been energized by the increased NATO presence in Turkey to protect the country from the chaos in neighboring Syria.
Between mid-2012 and early 2013, the DHKP/C carried out nearly a dozen attacks. The highest profile was a strike against the U.S. Embassy in Ankara in February 2013. A suicide bomber detonated his device at the entrance of the heavily fortified post, killing a Turkish security guard and wounding a journalist. The State Department now offers a reward of up to $3 million for information about Musa Asoglu, Zerrin Sari and Seher Demir Sen —the three top leaders of the DHKP/C.
Turkish authorities responded with series of raids in 28 provinces, during which police discovered plans to assassinate 22 high-level figures, including two former Turkish presidents. But these sweeps failed to contain the group. A month later, DHKP/C attacked the headquarters of the ruling Justice and Development Party (AKP) and the Justice Ministry, both in Ankara.
The antigovernment Gezi Park protests during the summer of 2013 were a gift to the DHKP/C, which cashed in on antiestablishment sentiment. Months after the Gezi protests ended, clashes continued in Istanbul neighborhoods such as Okmeydani, where the DHKP/C enjoys support.
The DHKP/C shows no signs of backing down in 2015. On New Year's Day, a DHKP/C terrorist hurled two grenades at Istanbul's historic Dolmabahçe Palace, which houses offices for the prime minister. Both grenades failed to explode. In claiming responsibility, the group said the attack was vengeance for Berkin Elvan, a 15-year-old bystander killed in the Gezi crackdown.
The DHKP/C also claimed responsibility for the Jan. 6 suicide attack in the Sultanahmet district of Istanbul. The attacker was subsequently identified as a Russian woman with links to jihadi groups. Remarkably, as details emerged, the DHKP/C realized that this was not their operative. The group recanted its claim of responsibility, but was quick to note that it had other militants in Turkey who were set to attack at any moment.
The group made good on its threat last week, when a DHKP/C militant—whose identity the group had mistakenly revealed in claiming the Jan. 6 attack—fired on a police checkpoint in Istanbul's popular Taksim Square. No casualties were reported, and the assailant fled the scene. Police identified her through camera footage and a manhunt is still underway.
DHKP/C's resurgence comes as Turkey's other terrorism challenges appear to be on the wane. Though it has attracted thousands of foreign jihadists, the Syrian civil war has yet to spill over into Turkey. While some unrest in Turkey's southeast persists, peace talks have resulted in a significant reduction in terrorist attacks by the Kurdistan Workers' Party, or PKK, the main Kurdish terror group.
But Ankara will need to tread carefully. If the Kurdish talks succeed, some of the most hardened Kurdish militants who refuse to make peace with Turkey could gravitate to the DHKP/C. Both are rooted in Marxist ideology, and there is a history of cooperation dating back to the 1990s.
Ankara must also keep an eye on the other major disaffected Turkish minority: the Alevis. They are traditionally leftist and, like the Kurds, have disproportionately flocked to radical movements, including the DHKP/C. Moreover, the Alevis have been at the center of the battles between the AKP and the DHKP/C in the marginalized Istanbul neighborhoods that were at the center of the Gezi protest movement.
The Turkish government is bracing for more DHKP/C attacks in the coming months. While police crackdowns have proved effective in the past, the DHKP/C hasn't been easy to dismantle. Most of the group's leadership resides in Europe, particularly in Germany and Greece.
Fortunately for Ankara, the group's tactics are limited to small-scale bombings and small-arms guerilla attacks, and most have failed due to faulty homemade weapons. Nevertheless, the frequency and targets of these attacks, typically aimed at the West and NATO, are cause for worry. Amid all the talk of Kurdish-separatist violence and jihadism, this little-known Marxist group has suddenly re-emerged as one of Turkey's more unlikely security concerns.
Mr. Schanzer is vice president for research at the Foundation for Defense of Democracies, where Ms. Tahiroglu is a research associate.