The EU warned President Recep Tayyip Erdogan on Monday to avoid inflammatory rhetoric as a diplomatic crisis between Turkey and the Netherlands deepened, with the Dutch envoy to Ankara summoned for the third day in a row.
The Netherlands blocked Turkish ministers from holding rallies over the weekend to boost support for an upcoming referendum on expanding Erdogan's powers.
In response, Erdogan twice accused fellow NATO member the Netherlands of acting like the Nazis, comments that sparked outrage in a country bombed and occupied by German forces in World War II.
Dutch Prime Minister Mark Rutte, who faces far-right challenger Geert Wilders in a key general election on Wednesday, said Erdogan's comments were unacceptable and that Ankara should apologise.
Adding fuel to the fire, the state-run Anadolu Agency quoted EU Affairs Minister Omer Celik as saying on Monday that the land passage component of Turkey's migrant deal with Europe should be reconsidered.
In an escalating standoff that risks damaging Turkey's already deteriorating relations with the European Union ahead of the April 16 referendum on constitutional change, Brussels sternly warned Ankara to avoid making the situation worse.
In apparent reference to Erdogan's comments, EU foreign policy chief Federica Mogherini and EU Enlargement Commissioner Johannes Hahn called on Turkey to "refrain from excessive statements and actions that risk further exacerbating the situation".
"It is essential to avoid further escalation and find ways to calm down the situation," they said in a statement.
NATO chief Jens Stoltenberg also urged Turkey and its NATO allies to "show mutual respect, to be calm and have a measured approach to contribute to de-escalate the tensions".