Turkish warplanes carried out a series of coordinated attacks against US-allied Kurdish forces in both northern Iraq and northeastern Syria today, killing more than 70 people, including at least 18 troops loyal to the Kurdish YPG, and pounding the area around the Iraqi city of Sinjar.

Attacks within Syrian territory targeted the city of Derik, in Hassakeh Province, targeting Kurdish military posts. The US arms and heavily backs the YPG, something Turkey has long complained about. The strikes, reflect long-standing Turkish threats to move against the Syrian Kurds.

But it’s not just Syria. The strikes around Iraq’s Sinjar were after PKK fighters in the area, with Turkey’s President Erdogan insisting that he will never allow Sinjar to become a PKK base of operation. The PKK established a presence in Sinjar during the expulsion of ISIS, and have been largely welcomed by the local Yazidi population.

The attacks on Sinjar also killed Iraqi Kurdish Peshmerga forces, who are supposed to be Turkey’s allies. Erdogan insisted that the killing of the peshmerga was unintentional and that he regretted that they got swept up in the strikes.

Turkey’s interventions in Syria have been commonplace, and strikes against PKK targets in Iraq’s far north were also not uncommon. This is something else, however, with more strikes centering around populated areas and against specifically anti-ISIS fighters.