This is reported by CNN Greece.
It is noted that the protesters gathered at the main entrance to the Palace of Music in Thessaloniki, where at this time the President of Greece Prokopis Pavlopoulos was to speak at an event dedicated to the Day of Memory of Greek Jews - martyrs and heroes of the Holocaust.
According to the TV company, the demonstrators tried to break through the police cordons into the concert hall.
Earlier, the Greek Parliament ratified the agreement with Skopje on renaming the Republic of Macedonia into the Republic of Northern Macedonia. The document was supported by 153 deputies.
The chairman of the European Council, Donald Tusk, approved the decision of the Greek parliament.