EU leaders urge Erdogan to show restraint post referendum victory

European leaders offered a guarded response to the referendum result granting Turkish President Recep Tayyip Erdogan sweeping new powers, with some senior EU figures saying it was the end of the country's decade-long attempt to join the bloc.

Berlin, Paris and Brussels signalled some serious concerns about the implications of the result, although their statements fell short of an outright condemnation, as reported by The Guardian.

Austrian chancellor Christian Kern issued a message that ruled out any future accession for Turkey to the EU.

"With what happened yesterday, (Turkey's) membership prospects are buried, in practical terms," he said, adding, "we are entering a new era."

Foreign Minister Sebastian Kurz added, "We can't just go back to the daily routine after the Turkey referendum. We finally need some honesty in the relationship between the EU and Turkey."

The 'Yes' camp won 51.41 percent in Sunday's referendum.

Several Turkish opposition groups, however, claimed irregularities during the voting process and the Organisation for Security and Cooperation in Europe (OSCE) said on Monday that the referendum fell short of international standards.

One Austrian observer Stefan Schennach alleged that "police twice blocked our observation".

In a newspaper interview, German foreign minister Sigmar Gabriel said that if Ankara were to bring back the death penalty as Erdogan had suggested, the move would be "synonymous with the end of the European dream".

"Any decision [about joining the EU] will not be on the agenda anytime soon. At any rate, joining would not work right now.," he said.

Turkey's accession talks with the EU began in 2005 but have barely progressed due to concerns over its human rights record and the reticence of some EU nations to include a majority muslim country.