Turkish President Recep Tayyip Erdogan has threatened to scrap a deal with the European Union to readmit migrants who have crossed illegally into Europe.
It comes amid a stand-off with European nations over their reluctance to allow Turkish ministers to hold campaign rallies in their countries.
In a televised speech, Mr Erdogan said the EU could "forget about" a migrant deal first struck in 2013 and revived last year.
Turkey had agreed to work to keep migrants from crossing into the EU in return for funds to help it deal with some three million refugees.
Mr Erdogan accused the EU of not sticking with a promise to grant Turkish nationals the right to travel visa-free in Europe.
He also sharply criticised a European court ruling in favour of curbs on wearing Islamic headscarves.
The comments were the latest in Turkey's bitter diplomatic spat with Germany and the Netherlands, which last week prevented two Turkish ministers from addressing Turkish citizens in Rotterdam in the lead-up to a referendum on constitutional reforms that would increase Mr Erdogan's powers.
One minister was escorted out of the country, while the other was denied permission to land.
Some German authorities have also blocked appearances by Turkish ministers trying to attend similar rallies.
On Thursday, Mr Erdogan reiterated angry criticism of the ban.
He also accused the EU of not sticking to a promise to grant Turkish nationals the right to travel visa-free in Europe.
"Now they're talking about the readmission agreement. What readmission? Forget about it," he said, referring to the migrant deal.
The agreement, which was initially reached in 2013, was revived last year, when Turkey agreed to help keep migrants from crossing into the EU in return for funds to help it deal with some three million refugees.
"You bar my minister from entering the Netherlands ... and then you expect us to grant access (to migrants)? There can be no such thing," he added.
Mr Erdogan also sharply criticised a European court ruling in favour of curbs on wearing Islamic headscarves, renewed accusations of "Neo-Nazism" against the Netherlands, and remarked that the Dutch Prime Minister Mark Rutte had lost Turkey's friendship despite winning elections there.
"What happened to your freedom to faith and religion," Mr Erdogan said.
"They have started a (Christian-Muslim) war. There can be no other explanation. I say this very openly, Europe is heading towards its pre-Second World War days."
Mr Erdogan ruled out any possibility of reconciliation with a new Dutch government to be headed by Mr Rutte.
"Oh Rutte, you may have come out (of the elections) as the first party, but you should know that you have lost a friend like Turkey," he said.
Meanwhile, Chancellor Angela Merkel's office said the German leader discussed the tensions between EU nations and Turkey with French President Francois Hollande in a phone call on Thursday.
The two reiterated that Mr Erdogan's insulting comments about Germany and other European countries - including "Nazi" comparisons - were unacceptable.
Mr Hollande stressed France's solidarity with Germany and other EU partners that Turkey has assailed, a German government statement said.
The two leaders agreed that appearances by Turkish politicians in Germany and France can be approved - but only if they are "registered in good time and transparently, and adhere strictly to German or French law".