Anger over a same-track collision between two trains in Greece that killed nearly 60 people spilled onto the streets of Athens Sunday as a massive protest devolved into chaos when some demonstrators hurled Molotov cocktails at police who responded with tear gas and stun grenades, writes abc7.com.

Shouting “That crime won’t be forgotten” and “Their policies cost human lives”, protesters packed the heart of Greece’s capital city, demanding the immediate bolstering of safety standards on the nation’s rail system that they contend have eroded since the country’s debt crisis from 2009 to 2018.

An estimated gathering of 12,000 protesters, most of them students and railway workers, filled Syntagma Square in the shadows of the Greek Parliament building and released black balloons into the sky to recognize those killed.

The peaceful protest escalated into chaos when a small group of demonstrators threw Molotov cocktails at police, according to Reuters. Video footage from the scene showed thousands of protesters dispersing from the square in all directions amidst a cloud of tear gas smoke.

Five people were arrested and seven police officers were injured when a group of more than 200 masked, black-clad individuals started throwing pieces of marble, rocks, bottles and firebombs at officers, according to the Athens Police Department.