Reuters | Additional reporting by Andreas Rinke in Berlin; Editing by Giles Elgood | October 26, 2019

BRUSSELS (Reuters) - Germany's defense minister presented to NATO her proposal for a security zone in northern Syria on Thursday, receiving support from Turkey and the United States but also a warning from the alliance's chief that it may need to involve the United Nations.

Annegret Kramp-Karrenbauer told allies that an internationally controlled zone would also need Russia, now the dominant power in Syria, if it was to protect displaced civilians and ensure the fight continues against Islamic State militants, diplomats said.

But she insisted at the meeting of NATO defense ministers in Brussels that the task of patrolling the Turkish-Syrian border could not fall to Russia and Turkey alone, telling reporters: "The status quo is not a satisfactory solution."

The idea, the first time Berlin has proposed a military mission in the Middle East, has at least served to steady an alliance that is badly shaken by U.S. President Donald Trump's decision to withdraw troops from Syria and Turkey's ensuing military operation launched on Oct. 9, diplomats said.

Europe were incensed by Turkey's cross-border offensive against Kurdish forces, which once fought along side the United States against Islamic State, while European Union governments have frozen arms sales in protest at Turkey's actions.

U.S. Defense Secretary Mark Esper, in Brussels on Thursday, said the Turkish incursion was "unwarranted".

Under Tuesday's deal between Russia and Turkey in the Black Sea resort of Sochi, Ankara has agreed to restrict its military operations in northern Syria to the border region. But European allies are still anxious about Turkish plans to remove Kurdish YPG fighters and their weapons from the border. 

Ankara views the YPG as terrorists linked to Kurdish insurgents in southeast Turkey.

European allies, who need Turkey's help to prevent Islamic State fighters in Syria fleeing to Europe, have long supported efforts to give the Kurds more cultural rights with the prospect of greater autonomy in the regions where they constitute a majority.

Kramp-Karrenbauer she had received reassurances from Ankara that the Turkish military would not result in a mass population resettlement or ethnic cleansing

"The Sochi agreement has not brought peace and it doesn't offer a basis for a political solution in the long run. We are looking for a solution that includes the international community," Kramp-Karrenbauer told reporters.

U.N PROCESS REQUIRED?

While few details were available, Turkey, Esper and NATO Secretary-General Jens Stoltenberg welcomed the German minister's plan, a rare proposal by a country wary of military missions in the Middle East. 

"More talks are necessary, but the Turkish minister said he is open to the proposal," one NATO diplomat said, referring to bilateral talks Kramp-Karrenbauer held with Turkish Defence Minister Hulusi Akar, who later also briefed all NATO ministers on Turkey's operations in Syria.

A second diplomat said German Chancellor Angela Merkel could discuss it with her Turkish, British and French counterparts at the NATO summit in London on Dec. 4, although there was no date for any meeting.

Stoltenberg said there was no call for a NATO mission in northern Syria and added that his understanding was that there could be a need for "a process in the U.N.". 

"Of course it's not possible today to say whether that will be easy or very difficult so I think this is a proposal which has to be discussed more in detail," he said. 

Esper said before the NATO meeting got under way that while he had not taken a detailed look at the German proposal, he was supportive, though Washington did not intend to contribute ground forces.

"I think it's fine. I think it is good for those countries who want to step up and help improve security in that part of the world," Esper said.

"It is something that we've been calling on our European partners to do for quite some time: it is to step up and do more," he added. Esper had been expected to meet his Turkish counterpart on Thursday, but the meeting may be postponed for scheduling reasons.