Syrian Kurds protest the Turkish offensive against Syria during a demonstration in front of the United Nation Headquarter in…
Syrian Kurds protest the Turkish offensive against Syria during a demonstration in front of the United Nation Headquarter in Erbil, Iraq Oct. 10, 2019.

UNITED NATIONS - U.S. diplomats are pushing back on Turkey’s incursion into northeastern Syria, labeling the military maneuver a “very big mistake” that could have significant consequences on the security situation in the region and beyond.

The criticism from Washington, echoed by European officials and members of the United Nation’s Security Council, came as Turkish artillery and war planes pounded Kurdish positions on the Syrian side of the border for a second straight day Thursday, forcing thousands of civilians to flee.

WATCH: Trump Threatens Turkey with Consequences Civilians Hurt in Offensive on Kurds

Turkey, in a letter to the United Nations, said its response would be “proportionate, measured and responsible.”

But top U.S. officials warned that even if Ankara can make good on such assurances, the consequences of its incursion into Syria are dire.

“This was a mistake for Turkey to do,” a senior U.S. State Department official told reporters late Thursday.

“The Turks have given us general guidelines of where they want to operate and what their military goals are,” the official said. “We think they’re all a bad idea.”

Urged Turkey to rethink operation

U.S. President Donald Trump, criticized for essentially giving Turkey a “green light” to proceed with the military operation by ordering U.S. special forces operating near the border to pull back, also pressed Ankara to rethink its decision.

“I hope we can mediate,” he later told reporters on the South Lawn of the White House, adding, “Turkey knows where I stand.”

Ankara is targeting Syrian Kurdish fighters it views as terrorists, but which most of the West consider to be key partners in the fight against militants from the so-called Islamic State terror group.

Turkish President Recep Tayyip Erdogan on Thursday claimed more than 100 “terrorists” have been killed, referring to the Kurdish fighters. He also warned he would send Syrian refugees to Europe if the European Union refers to Turkey’s operation as an “invasion.”

NATO Secretary General Jens Stoltenberg is expected to meet Friday with Erdogan in Istanbul. And top State Department officials have voiced hope that renewed efforts to “find our way to a cease-fire” could pay off, noting that Turkey previously has been willing to negotiate with the Kurdish groups it has targeted with its current military operations.

FILE - Syria's United Nations Ambassador Bashar Jaafari listens during a U.N. Security Council's meeting on Syria, Sept. 19, 2019, at U.N. headquarters.

Some U.N. Security Council members, though, went further Thursday.

“We call upon Turkey to cease the unilateral military action as we do not believe it will address Turkey’s underlying security concerns,” Germany’s Deputy U.N. Ambassador Jürgen Schulz said on behalf of the Security Council’s five European members plus Estonia, which will join the council in January 2020.

“Renewed armed hostilities in the northeast will further undermine the stability of the whole region, exacerbate civilian suffering and provoke further displacements, which will further increase the number of refugees and IDPs [internally displaced persons] in Syria and in the region,” he told reporters while flanked by his colleagues.

‘Maximum restraint’

Russia, which objects to the presence of the U.S.-led coalition against IS in parts of Syria, said, “All sides should exercise maximum restraint.”

Russian ambassador Vassily Nebenzia also signaled Moscow might block a unified statement from the 15-member Security Council if it fails to address “other issues that are in the Syrian file.”

In this photo taken from the Turkish side of the border between Turkey and Syria, in Akcakale, Sanliurfa province, southeastern Turkey, smoke billows from targets inside Syria during bombardment by Turkish forces, Oct. 10, 2019.

Meanwhile, the mainly Kurdish fighters in the region appealed Thursday for help to “save our people from genocide.”

The Kurdish-led Syrian Democratic Forces (SDF) said it “confronted an incursion attempt” by Turkish forces in Tal Halaf, and also a cell of Islamic State fighters in an area south of Ras al-Ayn. Kurdish official Diyar Ahmed said the area was surrounded by Turkish forces.

“Turkish planes have been striking from the air. At the same time, their heavy weapons haven’t stopped, they aren’t stopping in firing on the village, and civilians have been both wounded and lost their lives,” Ahmed said.

Also Thursday, the U.N. Refugee Agency warned that civilians are now in harm’s way, with tens of thousands of people on the move to escape the fighting as weather conditions worsen.

U.S. officials have sought to make clear that Turkey will bear full responsibility for protecting civilians and ensuring that no humanitarian crisis takes place.

U.S. United Nations Ambassador Kelly Craft address the U.N. Security Council after a failed vote on a humanitarian draft resolution for Syria, Sept. 19, 2019, at U.N. headquarters.

‘Will have consequences’

“Failure to play by the rules, to protect vulnerable populations, failure to guarantee that ISIS cannot exploit these actions to reconstitute, will have consequences,” U.S. ambassador to the United Nations Kelly Craft said.

In Washington, senior U.S. officials warned Turkey against engaging in ethnic cleansing and warned the Turkish military to avoid “indiscriminate artillery, air and other fires directed at civilian populations.”

“We’re not seeing significant examples of that so far but we’re very early [in the Turkish military campaign],” a State Department official who briefed reporters said, adding, “we’re very, very concerned.”

In the U.S., where both Democratic and Republican lawmakers have been critical of President Trump’s handling of the situation and of Turkey’s action, a group of Republican lawmakers announced their intent to introduce legislation to sanction Ankara.

“President Erdogan and his regime must face serious consequences for mercilessly attacking our Kurdish allies in northern Syria,” Republican Congresswoman Liz Cheney, chairwoman of the House Republican Conference, said in a statement.

Information from Reuters was used in this report.

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