Iran’s Foreign Ministry says Turkey has pledged to follow up on a recent shooting on the border that left an Iranian border guard dead and four others injured.

Foreign Ministry spokesman Bahram Qassemi said Tuesday that the fatal shooting assault took place north of the city of Maku, which lies in West Azerbaijan Province near the Turkish frontier.

The cause of the incident is still under investigation, Qassemi said, noting that the wounded are getting treatment at a hospital in Turkey’s northeastern Kars Province.

Earlier, Maku Governor Shahin Alizadeh had said two of the wounded were employees of the Iran Water Resources Management Organization.

In a phone conversation with his Iranian counterpart Mohammad Javad Zarif hours after the incident, Turkish Foreign Minister Mevlut Cavusoglu expressed condolences over the death of the Iranian border guard, according to Qassemi.

The top Turkish diplomat also pledged that Ankara would investigate the incident and inform Tehran of the results, according to Qassemi.

Cavusoglu blamed the shooting on Turkey’s outlawed Kurdistan Workers Party (PKK) militant group, said Qassemi.

The spokesman further said that Turkish Interior Minister Suleyman Soylu had assured Iranian ambassador to Ankara that the issue will be seriously pursued.