Turkey has threatened to end a refugee deal amid the deepening diplomatic crisis with the European Union.

Tensions are running high after Germany and the Netherlands prevented Turkish politicians from holding rallies intended to bolster support for a referendum on giving President Recep Tayyip Erdogan sweeping new powers.

Foreign Minister Mevlut Cavusoglu warned Turkey may cancel a migrant readmission agreement with the EU and said it is also reevaluating a $6bn (£4.9bn) refugee deal with the bloc.

Mr Erdogan later said in a televised speech the EU could "forget about" the migrant deal, first struck in 2013 in which Turkey agreed to take back migrants who travelled illegally to the EU in return for the promise of visa-free travel.

He accused the EU of not sticking with a promise to grant Turkish nationals the right to travel visa-free in Europe and went on to accuse Europe of starting a “clash” between Christianity and Islam after a ruling allowed employers to ban headscarves as part of wider restrictions on religious and political symbols.

Hundreds of pro-Turkey protesters clash with police in Rotterdam

"We may cancel the readmission agreement. The EU has been wasting our time on the visa liberalisation issue," Mr Cavusoglu said in an interview on Kanal 24.

"We are not applying the readmission agreement at the moment, and we are evaluating the refugee deal."

His comments come on the first anniversary of a deal to stop would-be refugees from crossing into Greece, in exchange for financial aid for those staying in Turkey and accelerated EU membership talks.The row escalated after the Dutch government banned a rally in Rotterdam at the weekend.

Mr Erdogan retaliated by branding the Netherlands "Nazi remnants." He also accused Germany of "fascist actions" after it cancelled several planned rallies.

EU leaders called the allegations offensive and "detached from reality."

In pictures: Turkey coup attempt Show all 17 1 /17 In pictures: Turkey coup attempt In pictures: Turkey coup attempt Turkish President Erdogan attends the funeral service for victims of the thwarted coup in Istanbul at Fatih mosque on July 17, 2016 in Istanbul, Turkey Burak Kara/Getty Images In pictures: Turkey coup attempt Soldiers involved in the coup attempt surrender on Bosphorus bridge with their hands raised in Istanbul on 16 July, 2016 Gokhan Tan/Getty In pictures: Turkey coup attempt A civilian beats a soldier after troops involved in the coup surrendered on the Bosphorus Bridge in Istanbul, Turkey, 16 July, 2016 REUTERS/Murad Sezer In pictures: Turkey coup attempt Surrendered Turkish soldiers who were involved in the coup are beaten by a civilian Reuters In pictures: Turkey coup attempt Soliders involved in the coup attempt surrender on Bosphorus bridge Getty In pictures: Turkey coup attempt Supporters of Turkish President Recep Tayyip Erdogan wave flags as they capture a Turkish Army vehicle Getty In pictures: Turkey coup attempt People pose near a tank after troops involved in the coup surrendered on the Bosphorus Bridge in Istanbul, Turkey, 16 July, 2016 Reuters In pictures: Turkey coup attempt Turkish soldiers block Istanbul's Bosphorus Brigde Getty In pictures: Turkey coup attempt A Turkish military stands guard near the Taksim Square in Istanbul Reuters In pictures: Turkey coup attempt Pierre Crom/Twitter In pictures: Turkey coup attempt Turkish soldiers secure the area as supporters of Recep Tayyip Erdogan protest in Istanbul's Taksim square AP In pictures: Turkey coup attempt People demonstrate in front of the Republic Monument at the Taksim Square in Istanbul Murad Sezer/Reuters In pictures: Turkey coup attempt Turkish soldiers detain police officers during a security shutdown of the Bosphorus Bridge Reuters In pictures: Turkey coup attempt Turkish Army armoured personnel carriers in the main streets of Istanbul Getty In pictures: Turkey coup attempt Chaos reigned in Istanbul as tanks drove through the streets EPA/TOLGA BOZOGLU In pictures: Turkey coup attempt Turkish President Tayyip Erdogan speaks to media in the resort town of Marmaris Reuters In pictures: Turkey coup attempt Supporters of President Erdogan celebrate in Ankara following the suppression of the attempted coup Reuters

Turkish hackers spread Nazi accusations across high profile Twitter accounts, posting pro-Erdogan messages from accounts including Amnesty International, BBC North America and Forbes.

A day after Dutch Prime Minister Mark Rutte was reelected, Mr Erdogan said he had lost the friendship of Ankara over the row.

Despite Mr Rutte's victory over the far-right populist leader Geert Wilders, the Turkish foreign minister claimed "holy wars will soon begin" in Europe.

“Now the election is over in the Netherlands...when you look at the many parties you see there is no difference between the social democrats and fascist Wilders,” Mr Cavusoglu said.

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French President Francois Hollande said the comparisons with the Nazis are unacceptable and expressed solidarity with Germany and the Netherlands.

Mr Erdogan, who survived a military coup last summer, has defended his plans to amass greater powers, saying Turkey needs greater stability.

His crackdown on dissenting voices among the judiciary and the media since the failed coup has drawn condemnation from the West.