ATHENS, Greece — Several thousand high school and university students blocked traffic in central Athens Friday in an anti-government protest against delays in an investigation into a 2023 rail disaster that claimed 57 lives.

Protesters marched through the city center, chanting “Murderers! Murderers!” as hundreds of police officers, many in riot gear, stood by.

The fatal head-on collision occurred near Tempe, in northern Greece, when a passenger train was incorrectly routed onto the same track as an oncoming freight train.

Delays in the disaster investigation have intensified pressure on the conservative government ahead of the two-year anniversary of the crash on Feb. 28. The tragedy already prompted massive public protests and political controversy.