ANKARA, Turkey -- U.S.-Turkey relations would be harmed if the United States goes ahead with its plan to partner with a Kurdish militia in Syria to clear the Islamic State from its de facto capital of Raqqa, Turkish Prime Minister Binali Yildirim said Thursday.
Turkey will not participate in the Raqqa operation, Yildirim said, if the U.S. does not heed the warning that was repeated this week by several Turkish politicians here, .
The U.S. military says it has already begun isolating Raqqa with Syrian Arab forces allied with the a Kurdish militia linked to a Kurdish separatist group that the State Department has designated as a terrorist organization.
Time is of the essence because the fight for Raqqa will be easier while the Islamic State leadership is preoccupied with defending western Mosul, the militants' last stronghold in Iraq, Col. John Dorrian, a U.S. military spokesman in Baghdad, told USA TODAY.
"This operation should be carried out jointly by the U.S. and Turkey," Yildirim said during a lunch with several American journalists at his office compound in Turkey's capital. "You cannot use one terror organization to fight another terrorist organization."
He warned that if the United States insists on working with the Kurds in Syria, "the friendship between the United States and Turkey will be damaged."
Yildirim said Turkey can prove that weapons the U.S. supplied to Kurdish allies have been used against Turkish forces by Kurdish separatists inside Turkey. Dorian said the U.S. military has not seen "any evidence the (Kurdish force) is doing anything to threaten Turkey."
The U.S., Turkey and other members of the coalition fighting the Islamic State have been consulting for months about the makeup of the force that will participate in the Raqqa operation, Dorrian said.
"For months, we have said we are open to a Turkish role in liberating the city," he said. But the liberating force should reflect the city's Arab population, "so you have a legitimate force ruling there," he said.
The Turkish-backed forces have yet to field a group large enough to tackle Raqqa and had a difficult time in liberating Al Bab, which "was a much smaller problem set," he said.
The Kurdish militia has secured major roads in and out of Raqqa, disrupting the Islamic State's ability to replenish manpower and supplies, as well as the group's ability to launch attacks on targets in the United States and Europe, Dorrian said.
The attack on the city could happen as soon as coalition partners decide on the makeup of the force, but it will go easier, meaning fewer coalition casualties while the fight in Mosul in ongoing, he said.
"The more problems they have at the same time, the more overwhelmed they're going to be," he said. "The command and control of (the Islamic State) has not been able to handle that in the past."
Yildirim said he hopes President Trump will abandon what Turkey considers the flawed policy of former president Barack Obama, whose administration developed the current Raqqa campaign.
Turkey wants Raqqa liberated by Syrian Arab troops it trained and supported in recent battles to free the cities of Al Bab and Jarabolus from the Islamic State, also known as ISIS. Those Turkish-supported forces recently took up positions near Manbij, where they clashed with Arab forces allied with the U.S.-backed Kurdish force.
Adding to the tensions in the region: Last week, those Kurdish militias were displaced by Russian-backed forces loyal to Syrian President Bashar Assad. Now the Turkish-backed forces cannot advance toward Raqqa without dealing with Assad's troops and Russia's air force.
And Turkey, whose leaders have called for Assad's ouster since the civil war began six years ago, will never cooperate with his regime, Yildirim said.
Turkish President Recep Tayyip Erdogan heads to Moscow Friday to discuss this issue, among others, with Russian President Vladimir Putin.