NATO Secretary General Jens Stoltenberg has warned Europe it must find a way to work with "important ally" Ankara.
Thousands of irregular migrants have gathered on the Turkey-Greece frontier since President Recep Tayyip Erdoğan gave migrants the green light to leave for Europe last week, as he seeks more support from the international community in Syria.
In an interview with AFP, NATO Secretary General Jens Stoltenberg called for a pragmatic approach, saying the European Union would have to find a way to cooperate with Ankara.
"We have to understand that when you speak about the migrant and refugee crisis we speak about a common challenge, which we have to address together," Stoltenberg said.
"The only way to address the situation on the border is by working together."
There was support for this view from Norbert Roettgen, chair of the foreign affairs committee in the German parliament and a contender to succeed Chancellor Angela Merkel.
"We have to face the reality and if you want to help the refugees you have to cooperate with Turkey," Roettgen said at the Institut Montaigne in Paris, calling for a dose of realpolitik.
"I cannot see a strategy without Turkey. Face the reality, it might not delight you but Turkey is the border state between Europe and the Middle East."
The migrant drama began after Russian-backed Syrian forces killed 34 Turkish troops in northern Syria, prompting Erdoğan to seek greater assistance from allies -- both military and to support 3.7 million refugees and migrants currently hosted in Turkey.
