Turkish President Recep Tayyip Erdogan has told the Syrian Kurdish PYD forces, who have worked with the United States in the past, “Pull yourself together” and keep east of the Euphrates River–or face military attack by Turkish forces.

Erdogan also accused the PYD’s forces–the People’s Protection Units (YPG and YPJ, divided by gender)–of “ethnic cleaning” in the non-Kurdish communities they have liberated from the Islamic State (ISIS) terrorist group.

“This was a warning. ‘Pull yourself together. If you try to do this elsewhere–Turkey doesn’t need permission from anyone–we will do what is necessary,'” Erodgan said, alluding to Turkish claims that they have already attacked the Kurdish PYD. In particular, Erdogan warned Kurdish forces not to declare a “canton,” or autonomous community, in Tel Abyad, a town near Turkey that had recently been liberated from ISIS control.

Erdogan also claimed the Kurdish forces had engaged in “ethnic cleansing” in liberated communities. “The PYD is committing ethnic cleansing here (of) Arabs and Turkmen. If the Kurds withdraw and don’t form a canton, there’s no problem,” he stated. “But if the mindset continues, then what is necessary will be done or we face serious problems.”

Erdogan further attacked Western countries, including the United States, who have cooperated with the PYD. “They don’t even accept the PYD as a terrorist organization. What kind of nonsense is this?” he asked. “The West still has the mentality of ‘My terrorist is good, yours is bad.'” The United States does not consider the PYD a terrorist group, though it does consider the Marxist Kurdistan Workers’ Party (PKK) a terror organization. Erdogan claimed the two are barely distinguishable, as 1,400 PKK terrorists are fighting the Islamic State alongside the PYD.

The PYD has worked with the United States to identify ISIS targets using ground intelligence and helped American planes make more precise airstrikes. In addition, a number of American citizens have left the United States to volunteer as fighters for the YPG and YPJ. Some Americans who aspire to join Kurdish ranks have begun online fundraising campaigns to buy their kit and travel to Syrian Kurdistan (Rojava).

Americans who die fighting for the Kurdish cause are revered as heroes. American Keith Broomfield, who was killed in battle in July, was given a hero’s welcome upon being returned to Kurdish territory and is praised as a “martyr.”

Turkey continues to view the PYD as a terrorist organization, however. Prime Minister Ahmet Davutoglu announced that Turkish forces struck the PYD twice this week. “We have said, ‘The PYD will not pass to the west of the Euphrates. We’ll hit them if they do,'” he told television viewers. “And we did hit them twice.”

Davutoglu has previously explained that supporting the PYD would result in arming the PKK, as both forces are cooperating to eradicate ISIS. “Whenever we find weapons in Turkey they will be destroyed, because the weapons dropped to PYD will be obtained by PKK too, and they are going to use them against the Turkish state,” he said in mid-October. “If you send weapons to PKK in Turkey, we will treat you as PKK and attack you inside Syria.”

In addition to working with the United States, the Russian government has been attempting to convince Syrian Kurdish leaders to work with the national Syrian army under control of dictator Bashar al-Assad. “We are contemplating this and will try to implement it,” President Vladimir Putin said of a plan to cooperate with “an armed opposition force that was genuinely ready” to fight ISIS. Russia is Assad’s most formidable ally and staked out a position on the Syrian battlefield this month.

On Thursday, Russian Deputy Foreign Minister Mikhail Bogdanov claimed that Russian officials have been consistently in contact with PYD forces on the ground. The Russian government has also alleged ties to the Arab Free Syrian Army, though these claims have been both confirmed and disputed by different members of the group.