EU foreign policy chief, Federica Mogherini, has warned that Turkey would be barred from joining the bloc if it reintroduces the death penalty to allow the execution of those involved in a recent failed coup in the country.

Speaking in Brussels where she has been meeting with European foreign ministers, Mogherini said that Turkey's return of the death penalty would bar its EU membership.

"Let me be very clear... no country can become an EU state if it introduces the death penalty," the EU foreign policy chief said on Monday.

The EU foreign policy chief noted that Turkey is part of the Council of Europe and is bound by the European Convention on Human Rights, adding, “Turkey is an important part of the Council of Europe and is bound by the European Convention on Human Rights, which is very clear on the death penalty.”

Mogherini had earlier warned the Turkish government against taking any post-coup steps that would damage the constitutional order.

US Secretary of State John Kerry also said during a visit to Brussels that the United States and EU call on Turkey to respect the rule of law in the crackdown following the attempted coup.

"We firmly urge the government of Turkey to maintain calm and stability throughout the country," Kerry told a news conference with Mogherini after talks with EU foreign ministers, adding, "And we also urge the government of Turkey to uphold the highest standards of respect for the nation's democratic institutions and the rule of law."

EU foreign policy chief, Federica Mogherini (R), flanked by US Secretary of State John Kerry delivers a speech as they give a joint presser after their bilateral meeting at the EU Headquarters in Brussels, on July 18, 2016. (AFP photo)

Meanwhile, Austria’s Foreign Minister Sebastian Kurz has warned that the idea of the reintroduction of the death penalty in Turkey is absolutely “unacceptable.”

This comes after Turkish President Recep Tayyip Erdogan has hinted that the death penalty may be reintroduced in Turkey to allow the execution of those involved in the coup bid.

The restoration of the death penalty, which was annulled in Turkey in 2004 under reforms aimed at joining the EU, would magnify differences between Turkey and the EU in the already-stalled talks over Ankara’s accession to the bloc.

Death penalty would end Turkey's EU accession talks: Germany

In strongly worded remarks, German Chancellor Angela Merkel's spokesman Steffen Seibert said on Monday that Turkey cannot join the EU if it reinstates the death penalty.

"Germany and the member states of the EU have a clear position on that: we categorically reject the death penalty," Seibert told a news conference in the German capital Berlin, adding, "A country that has the death penalty can't be a member of the European Union and the introduction of the death penalty in Turkey would therefore mean the end of accession negotiations."

The spokesman for the German government also stressed that Berlin had grave questions about President Erdogan's response to the foiled military takeover.

Seibert said he expected EU foreign ministers to address their concerns about the revival of the death penalty and disproportionate punishment in Turkey in a joint statement after a meeting in Brussels later on Monday.

"Everyone understands that the Turkish government and the Turkish justice system must bring those responsible for the coup to justice, but they must maintain the rule of law, and that always means maintaining proportionality ... and transparency."

German government spokesman Steffen Seibert (AFP photo)

The measures taken by Ankara following the failed coup attempt have prompted increasing international concern.

Turkish officials say that nearly 8,000 police officers have been suspended on suspicion of having links to the coup attempt at the weekend.

More than 7,500 people, including military generals and judges, have been arrested across the country after the failed coup.

EU commissioner Johannes Hahn, who is dealing with Turkey’s request to join the bloc, has said it appears that the Turkish government had prepared a list of people to be arrested even before the coup attempt.

A Turkish police restrains a man on the ground during an operation in front of the courthouse on July 18, 2016, in Ankara. (AFP photo)

The attempted coup began on Friday night and the violence and fighting between the putschists and government loyalists dragged into Saturday, when the coup was largely defeated.

A total of 290 people were killed in the abortive attempted coup d’état in Turkey.