US special forces in northern Syria came under fire by their NATO ally Turkey on Friday night, the Pentagon said, as Ankara pressed an offensive meant to eliminate Kurdish forces along the length of its border. There were no casualties.

“US troops in the vicinity of Kobani came under artillery fire from Turkish positions at approximately 9 pm local October 11,” a spokesman for the Department of Defense said in a statement to Asia Times.

The attack occurred “in an area known by the Turks to have US forces present,” it added.

The statement urged Turkey to “avoid actions that could result in immediate defensive action” and expressed strong rejection of the incursion into Syria.

The Turkish military earlier said its attack came in response to “harassment fire” from nearby the outpost.

Turkish President Recep Tayyip Erdogan received a green light for the operation during a call with US President Donald Trump last Sunday.

The operation is designed to cleave apart self-governing Kurdish cantons in Syria from Turkey’s own Kurdish-majority regions, and to create a corridor for the resettlement of up to two million Syrian Arab refugees.

Ankara has vowed to replicate earlier campaigns that resulted in massive displacement and rule by Islamist factions — raising fears that northeast Syria’s Christians, Kurds and Yazidis will be cleansed from the area. Already the UN says more than 100,000 people have bee displaced by the invasion.

The White House released a statement Sunday announcing troops would be clearing the way for the operation, effectively pulling the plug on a joint US-Turkish security mechanism which had required PKK-aligned Kurdish forces to remove their own defenses in a bid to placate Turkey.

Kurdish forces, who for the past five years served as America’s foot soldiers in the war against ISIS, were thus left exposed while US troops were ordered to pull back from the border.

The US outpost struck by Turkish artillery on Friday was located on a hill approximately two kilometers outside the border town of Kobani, according to an official with the Kurdish-led Syrian Democratic Forces.

“This is the first time this spot has been hit,” Syrian Democratic Forces (SDF) official Marvan Qamishlo told Asia Times. 

‘Middle East swamp’

Rivals of President Erdogan warned earlier this week that a broad military incursion into Syria runs the risk of creating new problems for Turkey at a time of economic duress.

Republican People’s Party (CHP) spokesperson Faik Öztrak told reporters in Ankara on Monday that Erdogan’s AKP was “incapable” of governing the country.

“They have brought the economy to ruins … They are looking for a way out, and they do not abstain from plunging into the Middle East swamp,” he said.

Öztrak went on to slam a deal announced by Trump on Sunday, in which he claimed Erdogan agreed to take custody of thousands of ISIS captives in Syria, currently held in a string of camps and detention centers under tenuous Kurdish control.

The only way to avert a quagmire with PKK-aligned Kurdish forces, the official said, would be to seek an accord with Syrian President Bashar al-Assad at the earliest opportunity.

“We are for the interests of our soldiers and nation. The shortest way to peace in Syria passes through the road from Ankara to Damascus.”

In the end, Erdogan’s key rivals rallied behind the flag and signed off on the operation, but experts say there is a limited public appetite for a protracted or bloody engagement should the ambitious plan get bogged down.

“The CHP and others even within the AKP have repeatedly said, ‘Why should we fight someone else’s war in Syria?'” said Kamal Alam, an analyst specializing in Syria and Turkey defense issues.

“No matter the Kurdish issue, no one sees going into Syria as a Turkish prerogative,” he told Asia Times.

“Turkish casualties will not go down well,” Alam added.

On Friday, the third consecutive day of the offensive, Turkey had already suffered three deaths among its servicemen, despite their intended role being to bolster allied Syrian Islamist factions.

“Turkey will pay a high price for this war. Economically … and with its sons,” said SDF spokesman Qamishlo.

“Erdogan thinks he is superman, that he is the Ottoman caliph, but this war will not be easy – not for him and not for us,” he told Asia Times. 

Should the conflict drag out, he warned, its scope could expand to elsewhere in the region.

Going it alone

While Erdogan secured the initial approval of Trump, the abandonment of America’s Kurdish allies prompted swift bipartisan outrage this week in Washington, and the White House’s reaction to the Turkish military operation was disjointed.

On Friday, Trump signed an executive order threatening sanctions on Ankara should he deem its actions destabilizing.

“We can shut down the Turkish economy if we need to,” Treasury Secretary Steven Mnuchin told reporters.

The unusual conditional order stressed it was “imperative” that Turkey ensure “not even a single ISIS fighter” be allowed to escape.

As the executive order was signed, Kurdish authorities said five ISIS detainees had managed to escape in the aftermath of a Turkish strike on one of the prisons.

CCTV footage released by the Kurdish forces purported to show guards relocating the prisoners, herding them through a courtyard. The claim could not be immediately verified.

Resistance against Turkey, the Kurds warned this week, will take precedence over guarding the prisoners.

Also read: In Turkey, Trump has a ‘conflict of interest’