Greek Prime Minister Kyriakos Mitsotakis said Monday he had tested positive for COVID-19 and would be self-isolating at home, a day after a trip to Istanbul.

Mitsotakis held talks Sunday with President Recep Tayyip Erdoğan and met with Ecumenical Patriarch Bartholomew I, who is considered the spiritual leader of the world’s Orthodox Christians.

Mitsotakis, wearing a mask, said in a video posted on Instagram that the result of his daily coronavirus test was positive on Monday, and he would therefore be working from home.

Mitsotakis held talks over lunch with Erdoğan in Istanbul on Sunday in a rare meeting between the leaders of the two neighboring countries. Relations between Greece and Turkey are strained over a series of issues, including territorial and energy exploration rights in the Mediterranean, which led to a naval standoff in mid-2020.

The two discussed bilateral and international relations, as well as Russia’s invasion of Ukraine, the Turkish presidency’s communications directorate said.

Earlier, Mitsotakis had met with the 82-year-old Bartholomew, who is based in Turkey’s largest city, and attended a church service there.

Both Erdoğan and Bartholomew are fully vaccinated and have previously tested positive for the virus – Erdoğan on Feb. 5 and Bartholomew in December. Erdoğan’s wife, first lady Emine Erdoğan, had also contracted the virus and both have since recovered, as has Bartholomew, who had suffered mild symptoms at the time.

Greece has seen a total of more than 2.6 million confirmed positive coronavirus cases and more than 26,500 deaths since the start of the pandemic. More than 7.5 million of the country's roughly 11 million population are fully vaccinated.