Turkish President Recep Tayyip Erdogan is due in Athens on Thursday for a historic two-day visit that will focus on a series of issues including territorial concerns in the Aegean and the extradition of eight Turkish officers that he broached in an exclusive interview with Skai and Kathimerini.

The first Turkish head of state to visit Greece in 65 years, Erdogan is to meet government officials on Thursday before travelling to Thrace in northern Greece on Friday for meetings with representatives of the region’s Muslim community.

Security in the capital will be tight with some 2,500 officers to be deployed, leading to the closure of much of the city center for most of the day. Erdogan is to land in Athens at 11 a.m. and meet with Tsipras at 1 p.m. before the two men deliver a joint press conference.

Talks with Tsipras are expected to cover a broad range of topics, though bilateral ties and a recent spike in tensions in the Aegean are expected to be high on the agenda.

In an interview with Alexis Papachelas for Skai TV and Kathimerini, Erdogan suggested that the Treaty of Lausanne, which set out the modern borders between Greece and Turkey, be updated, saying such a move could be beneficial for Greece and Turkey.

He would not discuss the possibility of revoking Ankara’s casus belli against Athens, however. Erdogan also insisted that Greece return the eight Turkish military officers who fled to Greece last year and were granted asylum after the Supreme Court rejected Ankara’s request for their extradition.

Tsipras, for his part, in an interview with Turkey’s Anadolu news agency, underlined the need for respect for the Treaty of Lausanne and for an easing of tensions in the Aegean where violations of Greek air space by Turkish fighter jets have increased.

Another major issue on the agenda is the refugee crisis amid an uptick in arrivals of migrants from Turkey.

Greece wants Turkey to honor an agreement with the European Union to crack down on human smuggling that was signed in March 2016 but Ankara’s degenerating relations with Brussels is a concern.

Economic relations will also be discussed, with a focus on energy, trade and transport, government sources said.