Iranian officials urged Turkey Tuesday not to launch an assault on Syrian Kurdish fighters in the north, after President Donald Trump’s decision to withdraw U.S. troops in the region. Trump has been criticized by senior military and Congressional officials for his decision to remove the small contingent of U.S. forces in the region.

The decision to withdraw U.S. forces is creating an uncertain future in the region, as the Syrian government under embattled President Bashar al-Assad is reaching out to its Syrian Kurdish population asking them to rejoin the government side, suggesting they had been abandoned by the United States.

Syria’s deputy foreign minister Faisal Mekdad made the statement on Syrian television saying if the Kurds don’t join the government they will “plunge into the abyss” — a reference to the expected Turkish incursion, according to the Associated Press.

Iran, which had a vested interest in Syria, made the announcement on its state TV reported Tuesday, according to an Associated Press report. The report noted that Foreign Minister Mohammad Javad Zarif called his Turkish counterpart, Mevlut Cavusoglu, to express Tehran’s opposition to the anticipated Turkish operation.

Kurdish fighters with the Syrian Defense Forces, an ally of the United States, said they were stunned Sunday when Trump made his announcement that U.S. forces would be pulled from the region.

Turkish forces appeared to have launched military airstrikes in a region Ankara calls the “Peace Corridor” along its border with Syria, suggesting that Kurdish fighters will use the border to launch terrorist attacks against Turkey. The two have been long time foes and decades of fighting

Zarif urged Turkey to respect Syria’s integrity and sovereignty.

Currently, Iran, Turkey and Russia have the so-called Astana group on the Syrian civil war, according to reports. Turkey, a NATO ally, has been criticized for its alliance with the group, whose efforts to find a solution with Syria often contradict the U.N. efforts and solutions currently being debated.

On Tuesday morning the Turkish Defense Ministry issued a statement on Twitter saying,”The establishment of a Safe Zone / Peace Corridor is essential for Syrians to have a safe life by contributing to the stability and peace of our region. The TAF will never tolerate the creation of a terror corridor at our borders. All preparations for the operation have been completed.”