Athens: German Chancellor Olaf Scholz on Thursday rejected Turkish claims on the sovereignty of Greek islands, at the start of an official visit to Athens.

Speaking to Greek daily Ta Nea ahead of an official meeting with Greek Prime Minister Kyriakos Mitsotakis, Scholz said it was "not acceptable" for a NATO state to question the sovereignty of a fellow member.

He also criticised the "more or less veiled military threats" towards Greece made repeatedly by Turkish President Recep Tayyip Erdogan and his senior officials in recent months.

Greece and Turkey, which are both members of the US-led NATO defence alliance, have feuded for years over maritime borders and energy exploration rights in the Aegean and east Mediterranean seas.

In an interview with French weekly Le Point also published Thursday, Mitsotakis said the language used in Turkey's "undeniably escalating rhetoric" was "unprecedented".

Whilst acknowledging that Erdogan's aggressiveness could be linked to a tough re-election campaign next year, Mitsotakis noted that Athens "cannot ignore that these statements confirm an aggressive and expansionist stance towards Greece".

"President Erdogan... now says he could invade my country during the night," the Greek premier said.

On his first visit to Greece as chancellor, Scholz on Thursday urged both states to resolve their differences "through dialogue and on the basis of international law".

Erdogan has lately accused Greece of "occupying" Aegean islands whose status was settled in treaties adopted after World War I.

In response, Athens accuses Turkey of conducting hundreds of illegal military sorties over the islands.

Last month, the United States said that Greek sovereignty was not in doubt, after Ankara lodged a protest over the deployment of Greek armoured vehicles on the islands of Lesbos and Samos.