Turkey launched a long-threatened military operation in northeastern Syria Wednesday targeting a US-backed, Kurdish-led militia alliance, after a US decision to pull back from the border and abandon its Syrian Kurdish partners. 

Turkish warplanes and artillery pounded positions of the US-backed Syrian Democratic Forces (SDF) across a wide front, before ground forces crossed the border late in the evening.

Turkish President Recep Tayyip Erdogan said that the offensive, dubbed "Operation Peace Spring," would "eliminate a terrorist corridor" along the border and bring "peace and tranquility" to the region.

Read more: Explained: Why Turkey wants a military assault on Syrian Kurds

He added that the Turkish military, together with Turkish-backed Syrian fighters known as the Syrian National Army, were targeting Kurdish militants and the "Islamic State" (IS). 

The launch of the operation caused a crescendo of international criticism and concern.

Turkey considers Kurdish YPG militia to be linked to the Kurdistan Workers' Party (PKK), which has fought a four-decade insurgency for Kurdish rights against the Turkish state. The YPG is the main component of the SDF, an militia alliance that includes Arab and Christian fighters. 

The Turkish operation began after US President Donald Trump announced on Sunday that US troops would pull out from the border region, essentially allowing NATO ally Turkey to begin military operations against the US-backed force of 60,000 fighters that has led the battle against IS.

Turkey wants to create a 32-kilometer-deep, 480-kilometer-long (20 miles deep, 300 miles long) "safe zone" inside Syria along the border. It then plans to resettle at least 1 million of its 3.6 million Syrian refugees who hail from other parts of Syria into mostly Kurdish populated areas. 

"This operation has nothing to do with IS. This is about clearing Turkey's border of Kurdish forces," said Nicholas Heras, a Middle East expert at the Center for a New American Security, a Washington think tank. "Turkey is selling a lie."

Meanwhile, US Secretary of State Mike Pompeo defended the USA's decision to withdraw troops from the area, saying "the Turks have a legitimate security concern," and that "they have a terrorist threat to their south."

Read more: 'Islamic State' resurgence a 'very real possibility' after US exits Syria

'Panic' as attack began 

The Turkish ground assault appeared centered on a 100-kilometer stretch between Tel Abyad and Ras al-Ain.

Meanwhile, near the region's largest city, Qamishli, plumes of smoke could be seen rising in the sky. There were also reports of strikes in Kobane and other areas of the region. 

Turkey's Defense Ministry said 181 targets had been hit by midnight, local time. They tweeted on Thursday morning that they had "neutralized three members of a separatist terrorist organization." 

The Syrian Observatory for Human Rights, a war monitoring group, said there have been 15 deaths, including eight civilians. 

An SDF spokesperson said on Twitter that Turkish fighter jets were striking targets and "civilian areas" in the region.

The was a "huge panic" as thousands of people fled the border regions to the south and in the direction of the Kurdistan Region of Iraq, the SDF said. 

It vowed to resist any Turkish offensive across the border.   

US and Kurdish officials said the SDF had suspended operations against IS to focus on defending against a Turkish ground operation. The SDF has warned that around 11,000 IS fighters in SDF prisons could flee in any chaos. Tens of thousands of IS family members are in other camps across SDF-controlled areas. 

Syrian Kurds are warning of ethnic cleansing and demographic engineering of areas along the border.

The International Rescue Committee said more than 300,000 people could be displaced in the Turkish offensive.

It warned that humanitarian services to hundreds of thousands of people, many previously displaced during the eight-year Syrian civil war, could be impacted. 

Read more: Trump's Syria withdrawal: Who stands to gain? 

Trump sends mixed signals in face of backlash

Trump's decision to withdraw US troops from the border has been widely criticized in Washington as a betrayal of its Kurdish allies in northern Syria and risking a resurgence of IS.  The backlash has forced the president to veer from green lighting the operation to threatening the Turkish economy and distancing himself from the operation.

"The United States does not endorse this attack and has made it clear to Turkey that this operation is a bad idea," Trump said after the assault began, adding that he did not want the United States involved in "endless, senseless wars" in the Middle East. 

Trump added: "Turkey is now responsible for ensuring all IS fighters being held captive remain in prison and that IS does not reconstitute in any way, shape, or form."

Trump also defended the decision by saying that Kurds "did not help us in Normandy" in the Second World War.

It's unclear how Turkey would take control of imprisoned IS fighters, who are in SDF detention several hundred kilometers from the Turkish border.

Read more: Turkey threatens to 'open the gates' to Europe for refugees

In Washington, Democratic and Republican lawmakers in a rare act of bipartisanship condemned Trump and the Turkish operation against the SDF as a threat to the fight against IS.  

Senator Lindsey Graham, a staunch Republican ally of the president, said Congress would "make Erdogan pay a heavy price" as he joined Democratic lawmakers in preparing a bipartisan sanctions bill against Turkey. 

Earlier, Graham threatened to kick Turkey out of NATO. 

Third operation in Syria

Turkey has carried out two previous military operations inside Syria to thwart Kurdish ambitions, carving out areas of control in northern Aleppo province and the Kurdish populated enclave of Afrin. 

In Afrin, rights groups and the UN have accused Turkish-backed rebel forces of gross human rights violations, including forcible displacement, confiscation of property, pillaging, arbitrary arrest, torture, kidnapping and extortion. 

cw,wmr,ed/dr (Reuters, dpa, AP)

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