An ISIS “web portal” has released a statement in response to Turkey announcing its first airstrikes against the terrorist group alongside the American government, calling Islamist President Recep Tayyip Erdogan an “infidel” and threatening retribution for Turkey’s “crimes” against them.

Turkish newspaper Zaman translates the message released on Monday, which appeared on Turkish radical site Hilafettakip.com, “which is thought to be affiliated with ISIL.” The message vowed to punish Turkey “for the crimes that the country has committed” and accuses Erdogan of being an “infidel” working to help American “crusaders” crush Islam:

The web portal called President Recep Tayyip Erdoğan an “infidel” and an “accomplice” who supported the US military intervention in Iraq in 2003. The site also claimed that Erdoğan is facilitating “the crusaders,” allowing the US expanded access to İncirlik Air Base so it can support the regime of Syrian President Bashar al-Assad and the terrorist Kurdistan Workers’ Party (PKK). Kurdish forces that have links with the PKK are fighting ISIL in northern Syria.

Erdogan, the head of Turkey’s Justice and Development Party (AKP), is a self-proclaimed Islamist who has rejected the existence of “moderate” Islam and insisted on multiple occasions that medieval Muslims discovered America centuries before the Spanish-funded mission by Christopher Columbus. The Islamic State has nonetheless branded him an “infidel” and “collaborator.”

Another Turkish website, Diken, notes the message claimed that Erdogan was helping anti-ISIS forces in Kobani, Syria, where Kurdish militias ultimately eradicated the terrorist group. Kobani lies on the Turkish border, making it strategically indispensable to ISIS.

The Islamic State has previously claimed the Turkish government is collaborating not just with Syrian Kurdish elements, but with the Kurdistan Workers’ Party (PKK), a Marxist terrorist group the Turkish government has vowed to destroy. Kurds have long complained that Erdogan’s government has put too much emphasis on destroying the PKK and not enough of curbing ISIS, with many airstrikes allegedly against the Islamic State actually hitting Kurdish strategic targets.

This attack is a response to the announcement this weekend that Turkey had engaged in its first collaborative airstrike campaign with the United States since announcing such a campaign in July. “Our fighter aircraft together with warplanes belonging to the coalition began as of yesterday evening to jointly carry out air operations against Daesh targets that constitute a threat against the security of our country,” the Turkish Foreign Ministry announced Saturday. Turkey began bombing Syria following a terrorist attack in the town of Suruç attributed to the Islamic State, which killed mostly Kurdish Turks who had organized to make a humanitarian trip to Kobani.

The U.S. State Department responded to the news of Turkey’s new airstrikes positively. “Turkey, in terms of combating ISIS and dealing with the inflow of Syria refugees, has been above and beyond what we might expect,” said State Department Spokesman Mark Toner this week, praising Turkey for “doing all it can” in the fight against ISIS.