Turkish EU Affairs Minister Omer Celik warned the ambassadors Monday that relations were "in a very fragile period" as Brussels readies what is expected to be a very negative report on Turkey's long-stalled membership talks.
In a statement issued on behalf of all 28 member states, EU foreign affairs head Federica Mogherini said they were watching developments in Turkey with "grave concern."
The EU condemned the July 15 coup and recognized Turkey's right to "take proportionate action," it said, AFP reported.
But at the same time, the bloc was calling on Turkey "to safeguard its parliamentary democracy, including the respect for human rights, the rule of law, fundamental freedoms and the right of everyone to a fair trial, also in conformity with its commitments as a candidate country," it said.
Turkey had the right to defend itself against the outlawed Kurdistan Workers Party (PKK), which the EU lists as a terrorist organization, but actions must fully respect "the basic principles of democracy, proportionality and respect for human rights," it added.
The statement, which followed similar warnings on Friday issued in Mogherini's name, detailed a litany of concerns, beginning with the possible reintroduction of the death penalty which the EU has warned repeatedly would immediately end Turkey's accession talks.
It also referred to President Recep Tayyip Erdogan's massive crackdown on the media and last week's arrests of the leaders of the pro-Kurd Peoples' Democratic Party (HDP) and several MPs.
These "are extremely worrying developments which weaken the rule of law, the respect for human rights and fundamental freedoms and compromise parliamentary democracy in Turkey while exacerbating tensions in the southeast and further polarizing Turkish society in general," the statement said.
The latest annual review of Turkey's EU membership talks is expected to be published on Wednesday amid reports it will talk of a "severe regression" in freedom of expression.
An EU candidate state is obliged to meet the bloc's democratic and rights standards and the talks with Turkey, which formally began in 2005, have been dogged by repeated criticism of Ankara's record.
Celik told the EU ambassadors "it is not acceptable that some of our friends in Europe use one sentence to say that they are standing next to us and then come up with nine sentences of criticism."