Erdogan stepped up his denunciations of Western policy on migrants in a speech in Ankara, confirming he had threatened EU leaders at a summit meeting in November that Turkey could say "goodbye" to the refugees.
Alarm is growing in EU capitals that thousands of migrants are still crossing the Aegean daily from Turkey after over a million made the perilous journey last year.
NATO has agreed to send a naval group to the Aegean to crack down on people-smugglers feeding the influx of migrants, while Greece is considering sending anyone picked up in the waters back to Turkey.
Erdogan said Turkey had every right to turf the refugees out of the country if it so wished.
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"We do not have the word 'idiot' written on our foreheads. We will be patient but we will do what we have to. Don't think that the planes and the buses are there for nothing," Erdogan said.
Greek website euro2day.Gr had reported that Erdogan made the threat to EU Commission president Jean Claude Juncker in November, quoting him as saying: "We can open the doors to Greece and Bulgaria anytime and put the refugees on buses."
Turkey is already hosting 2.5 million refugees from Syria's civil war and hundreds of thousands from Iraq and is increasingly bitter it has been left to shoulder the burden.
The EU has agreed to give Ankara three billion euros (USD 3.3 billion) in financial aid for the refugees, but the funds have yet to be handed over two-and-a-half months after they were agreed.