The first official visit by a Turkish president to Greece in six decades got off to a tense start yesterday after Recep Tayyip Erdogan said the countries needed to reassess their border and demanded the extradition of suspected coup plotters.

Uneasy allies in Nato and at odds over a host of issues from ethnically split Cyprus to air space, diplomatic niceties were set aside after early remarks by Mr Erdogan to Greek media that a treaty defining their borders may need reviewing.

The Turkish president was quoted in an interview suggesting a revision to the 1923 Treaty of Lausanne, which established the borders of modern-day Turkey.

The president has made similar comments in the past about the peace treaty, but his repetition on the day before his arrival in Athens came as an unwelcome surprise to his hosts.

“The Treaty of Lausanne defines the territory and the sovereignty of Greece and of the European Union and this treaty is for us non-negotiable,” Greek president Prokopis Pavlopoulos responded to his Turkish counterpart.

"It has no flaws, it does not need to be reviewed, or to be updated.”

Historical tensions between Greece and Turkey, which have brought the two countries to the brink of war on three occasions since the 1970s, remain.