An estimated 60,000 protestors gathered at Syntagma Square on Sunday to protest the Prespes Agreement on the renaming of the Former Yugoslav Republic of Macedonia to Republic of Northern Macedonia.

Clashes soon broke out as a group of of around 30 masked youths broke out from the crowds, and tried to break through the police line in front of Greek Parliament.  Scuffles took place as protestors threw stones at the police. One protestor, draped in a Greek flag, attacked a law enforcement officer with a stick, and the police responded by spraying tear gas at the crowd.

At least 25 officers were injured and hospitalised as a result of the clashes, and there were 12 people detained as part of an investigation.

A number of citizens also sought medical attention after experiencing difficulties in breathing as a result of the tear gas.

Spanish author/filmmaker Petro Olalla attended the protest and posted a photo of a tear gas can that contained chemicals banned by international treaties, whereas other protestors pointed to cannisters that had expired in 2017.

Atenas. Plaza de la Constitución. Ahora. Los griegos se manifiestan contra la usurpación flagrante de su historia y el gobierno los fumiga con gas CS caducado (prohibido para la guerra por la Convención de Armas Químicas pero autorizado como antidisturbios en condiciones de"paz") pic.twitter.com/Ec9g2NmnqK

— Pedro Olalla Writer (@pedro_olalla) January 20, 2019

The Prespes Agreement is a landmark accord that hopes to put an end to the 28-year dispute between Greece and neighbouring FYROM, however protestors believe that it makes too many concessions.

Greek leftist Prime Minister Alexis Tsipras narrowly survived a vote of confidence last week ahead of voting set to take place this week for the ratification of the agreement.