Turkish action in Syria is just one part of a chain reaction that experts believe could lead to another humanitarian crisis in Europe.
Hundreds of refugees have already flocked to Turkey's border with Greece — or arrived in dinghies on the island of Lesbos — after Ankara said it would no longer prevent their passage to Europe.
The comments have prompted criticism from human rights experts who say Turkey has used the refugees as "bargaining chips" to force the EU to intervene in escalations in Syria.
It comes a day after 33 Turkish soldiers were killed in an airstrike in Idlib, where intense fighting has already sent thousands of Syrians fleeing from their homes.
Here we speak to several experts to assess the EU's role in Turkey, ask whether Europe is facing another migration crisis and determine if the bloc has a responsibility to act.
Why should Europe be worried?
An escalation to continued fighting in Syria could start a chain reaction reminiscent to the fallout from the continent's migration crisis, which began in 2015.
If Turkey is facing another influx of refugees fleeing the war-torn country, the newly relaxed border conditions would mean Europe is facing the same prospect, too.
Research fellow Luigi Scazzieri, from the Centre of European Reform (CER), told Euronews this could lead to "hundreds of thousands of refugees" arriving in the EU, and could see "a break down of its relationship with Turkey and greatly straining the EU's cohesion".
Looking closer, conflict analyst Ruslan Trad said it bothered him the EU was "late" to respond to issues "already knocking at the door".
He said: "The EU is divided, but let's remember what happened after the 2015 refugee wave - populist governments, Brexit, internal tensions.
"The EU is not better prepared today. The lack of a common foreign policy and understanding of the situation on the ground makes the Union a latent observer of events."
Why is Turkey threatening to open the border?
Turkey's comment to relax border controls to EU member states would breach a pact made in 2016 to curb the flow of migration to Europe.
But Ankara is also embroiled in an incursion into northern Syria to satisfy its own interests in the region and to create the much talked about "safe zone" along its border.
This has been met with criticism and a sense of reluctance to get involved from the EU and allies of the North Atlantic Treaty Organisation (NATO), of which Turkey is a part.
So — by threatening to break the 2016 pact and bring European interests into the fold — this could force the EU and other NATO allies to act in a conflict they otherwise wanted no further part in.
"The emergence of a humanitarian crisis near Europe’s borders unrivalled in its severity since the Yugoslav wars should convince Western nations to reassess the risks of non-intervention," Sinan Ulgen, the chairman of Istanbul-based think-tank Edam, wrote in Foreign Policy magazine.
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Did Turkey have any other option?
"There were certainly more options, but very few left in the early 2020s," Trad said over email.
The co-founder of De Re Militari Journal added that Western powers couldn't expect Turkey — which already hosts 3.5 million refugees — to continue as it is for much longer.
He added: "To me, this is a wrong but expected solution."
Does the EU have a responsibility to act?
Experts have encouraged the EU to have a stronger response in protecting refugees, but also in taking a bigger part in finding a long-term solution for peace in Syria.
"Idlib is a textbook case of the sort of situation in which international humanitarian intervention is warranted," Ulgen wrote.
Meanwhile, Scazzieri said it was in Europe's best interests to "contain the crisis".
This can be done, he added, by increasing "support to refugees in Turkey and also pushing Russia to halt fighting in Syria."
What about in the meantime?
Ulgen further suggested a joint EU-NATO humanitarian mission in order to help those displaced in Idlib, while Amnesty International has criticised the use of refugees as "bargaining chips" in a "deadly political game".
The organisation's deputy research director Massimo Moratti released a statement on Friday calling for the EU to do "far more to share responsibility" for refugees arriving in Turkey.
This would include "financial support and ensuring safe pathways to Europe," he said.
"European member states shoulder their fair share of responsibility."