Turkish President Recep Tayyip Erdogan has overdone it with his challenging of Greece’s sovereignty and Greek territorial waters, former US Ambassador to Greece Nicholas Burns told the online 31st annual Greek Economic Summit of the American-Hellenic Chamber of Commerce on Wednesday.

Also one of US President-elect Joe Biden’s electoral campaign advisors, Burns added that it is incumbent upon Turkey to step back, end these very aggressive actions against both Greece and Cyprus, and join the diplomatic dialogue.

Referring to Turkey’s actions in the Aegean and the Eastern Mediterranean, its involvement in Syria, in Libya and in Nagorno-Karabakh, as well as its procurement of S-400 missile systems, Burns said that “Turkey has become a great headache for NATO and for European countries.”

Turkey’s authoritarian stance concerning its own domestic issues is a problem for a democratic alliance like NATO, he added, and called it a problem that needs to be tackled by both the US and the EU.