Turkey would allow refugees to stream into Europe if EU leaders continued to back away from their promises, President Recep Tayyip Erdogan said on Friday.
Erdogan's statement comes a day after the European Parliament voted for the temporary suspension of accession talks with Ankara.
He said that Turkey was hosting 3.5 million refugees – mostly Syrian – and had spent $15 billion in the process.
"If you go too far, the border gates will be opened," Erdogan was quoted as saying by Anadolu Agency during the Second International Women and Justice Summit in Istanbul.
Turkey and the EU signed the refugee deal on March 20, 2016, in which Turkey agreed to take back refugees who cross into Greece illegally. According to statistics from Turkey's Interior Ministry, there are currently 140,000 undocumented refugees.
"It is us, who are feeding the 3-3.5 million refugees in Turkey. You [the EU] broke your promises," the Turkish president added.
"It wouldn't matter if all of you approved the (European Parliament) vote… Neither me nor my people will be affected by these empty threats," Erdogan said.
The vote is symbolic and nonbinding. It comes ahead of a crucial meeting between Europe's foreign ministers next month, where Turkey's decades-old effort to join the EU will be discussed.
Austria has led calls to stop the membership talks. Austrian Chancellor Christian Kern said in August that the democratic and economic disparities between Turkey and the EU are too great.
Turkey also summoned the Austrian ambassador to the its Foreign Ministry in August over a rally held in Vienna in support of the PKK, which is designated as a terrorist organisation by Turkey, the US and the EU.
For now, Germany, France and most other EU states back continued engagement and fear putting at risk Erdogan's collaboration on migration.
The German Foreign Ministry spokesperson said on Friday that the EU and Turkey should stick to the refugee agreement.
Under the EU-Turkey deal, undocumented refugees will be repatriated back to Turkey and EU countries will resettle others from Turkish refugee camps in a "one in, one out" system.
"If one looks at the facts, then it is the case that both sides are sticking to the agreement and we hope that remains the case, as it is in the interests of both sides," Sawsan Chebli, the German spokesperson, said on Friday.
Part of the deal includes the EU's commitment to give visa-free travel to Turkish citizens. Besides travel liberalisation, the EU has promised 3 billion euro in financial aid.
Erdogan said the bloc has given only 700,000 million euro, while the United Nations' financial aid to refugees in Turkey is $550,000 million.
The EU parliament's resolution accuses Turkey of going overboard with a crackdown against perpetrators behind the July 15 coup attempt that left more than 240 people dead.
Turkey accuses the EU of a double standard because the bloc is focusing on the arrests, while remaining relatively mute on the coup attempt.