Turkish President Recep Tayyip Erdogan says Greek authorities are acting like the Nazis as they resort to violence in preventing thousands of refugees from crossing the Turkish border into Greece.

At a televised speech on Wednesday, Erdogan also referred to Greek authorities as “barbarians” and “fascists,” saying he would keep his country’s border open for refugees to cross to Europe until the European Union (EU) met all his demands.

“There is no difference between what the Nazis did and the images we are seeing from the Greek border,” Erdogan said.

“With the warming of the weather in the spring, the influx of irregular migrants heading to Europe will not be limited to Greece but spread all over the Mediterranean,” he said.

Tens of thousands of refugees have been trying to cross into Europe via Turkey since Ankara late last month decided to loosen controls on refugees seeking to reach Europe through its territory, violating a 2016 deal with the EU. That has caused tensions on Turkey’s border with Greece, where Greek forces have been clashing with the refugees to block them.

Greece has tear-gassed the refugees and is accused of beating and stripping them of their belongings if they make it across the border. Athens has denied those accusations.

Greece and the EU have, in turn, accused Ankara of deliberately encouraging the refugees to cross the border as a way of pressuring European leaders into offering more financial assistance or backing Turkey’s campaign in Syria.

Earlier, Erdogan made an unsuccessful trip to Brussels to resolve the tensions with the EU over Turkey’s decision regarding its border controls.

In March 2016, Turkey and the EU sealed a deal intended to stem the flow of refugees from Syria and other troubled countries to Europe in return for financial and political rewards for Ankara, including visa liberalization. Ankara, however, failed to meet the 72 conditions demanded by the EU for the visa exemption to be approved.

Ankara says the deal needs updating now.