True to Erdogan's prior threat that Europe would see 18,000 to as many as 30,000 refugees pour across European Union borders on Saturday after Turkey 'opened the gates,' it's being reported that the number of migrants at Evros — a key land border between Turkey and Greece — has now reached 15,000.

Throughout Saturday the area became a war zone as thousands of refugees, urged on by Turkish authorities, attempted to cross into Greece en masse.

In places like the now completely closed Kastanies crossing (sealed by the Greek side as Turkish guards stood down and let migrants pass freely), thousands are stuck in 'no man's land' between the borders, with the situation fast descending into chaos.

#Exclusive: Number of migrants at #Evros has now reached c. 15.000. Frontex to redeploy forces from other points to assist Greece in guarding EU external border with Turkey, @derspiegel has learned. Frontex Rapid response also a possibility but not yet https://t.co/RZ1G32zwOb — Giorgos Christides (@g_christides) February 29, 2020

According to the Greek daily Ekathimerini:

This is the first time such a large group of migrants and refugees has attempted a crossing en masse at Evros, a move that Greek authorities are treating as a consequence of the announcement from the Turkish government on Thursday night that it would no longer prevent migrants trying to reach the European Union.

Germany's Der Spiegal published footage showing migrants hurling tear gas grenades at Greek police, reportedly canisters provided by Turkish security themselves.

#Evros now: Videos obtained by ⁦⁦@derspiegel⁩ show migrants throwing tear gas used (and acc to GR officials and simple logic provided) by Turkish Gendarmerie at Greek police preventing them from crossing the fence, near Kastanies. Human beings shamelessly weaponized pic.twitter.com/daWRZz9P1M — Giorgos Christides (@g_christides) February 29, 2020

Greek Prime Minister Kyriakos Mitsotakis earlier vowed that "no illegal entries into Greece will be tolerated" - and has authorized a militarized response to seal border crossings with Turkey, which has included naval patrols in the Aegean to thwart migrant boats from passing.

At the Kastanies crossing Greek guards were seen firing tear gas on tightly packed groups of hundreds of migrants:

Guards on Greece’s northeastern land border with Turkey made “deterrent use” of tear gas to disperse some 500 refugees and migrants trying to enter the country and the European Union after Ankara loosened controls on migrant flows. Turkish border guards “have disappeared since this morning,” the mayor of the Greek border town of Orestiada, Vassilis Mavridis, said, adding that the group tried to enter through the Kastanies crossing.

Via AFP/Al Jazeera: Buffer zone on the Turkey-Greece border, at Pazarkule, in Edirne district, on February 29, 2020.

It's been confirmed that well over 30,000 mostly Syrian refugees and migrants on the their way to European border areas.

Unconfirmed reports say Athens may now even be sending tanks in support of commandos and helicopters already said to be there assisting in sealing the Evros border area.

36,776 migrants & refugees have left Turkey for Greece since the 33 Turkish soldiers were killed in Syria on Thursday. Turkey carrying out its threat to open up the migrant trail again in response to lack of Western support for its Syria fight https://t.co/DsY45jBzW2 — Liz Sly (@LizSly) February 29, 2020

Angry over Thursday's Russian-Syrian airstrike on Turkish troop positions in Idlib, which killed 33 Turkish soldiers, President Erdogan warned Europe to brace itself:

"We will not close these doors in the coming period and this will continue."

Erdogan continued: "Why? The European Union needs to keep its promises. We don’t have to take care of this many refugees, to feed them," he said.

1000s of migrants/refugees today again flock to Turkish-Greek border near Edirne. Crowd is growing by the hour.



You can see in this video by @egemengok_ that there are no guards on Turkish side.



People walking freely into no man's land only to be blocked by Greek border guards. pic.twitter.com/bZo4fxFWTT — Jenan Moussa (@jenanmoussa) February 29, 2020

By all accounts of the increasingly chaotic and strained situation on the ground, things are about to break. It does appear we're seeing Erdogan's "open the floodgates" in action or at least the very early beginnings.

Happening in Thermis, #Lesvos right now.



Migrants have reached the port in a rubber boat. A crowd is now stopping them from disembarking.



There are reports of violence against journalist. Some roads around #moria camp are being blocked by locals. No authorities on the scene. pic.twitter.com/GEejOnbMAT — Max Zander (@The_Max_Zander) March 1, 2020