A total of 13 soldiers were wounded late Monday, Sept. 21 in an attack by the outlawed Kurdistan Workers’ Party (PKK) in the Başkale district of Van province, Hurriyet Daily News reports.

PKK militants remotely detonated a hand-made explosive placed on the Başkale-Hakkari motorway at around 11:30 p.m. as a military vehicle was passing by. The armored vehicle was overturned as a result of the explosion, wounding 13 soldiers inside.

The wounded servicemen were taken to Başkale State Hospital and later transferred to a university hospital with helicopters after receiving initial treatment.

An investigation is underway to determine the militants responsible for the attack.

The PKK began its separatist insurgency in 1984, triggering a conflict that has killed more than 40,000 people. The group, which says it is now fighting for greater Kurdish autonomy, is designated a terrorist organization by Turkey, the European Union and the United States.

President Tayyip Erdogan has promised the fight will go on until "not one terrorist is left". The conflict has flared up as Turkey prepares for a parliamentary election on Nov. 1 following an inconclusive June vote.