BELGRADE, Serbia (AP) — Thousands of mainly young people in Serbia embarked on a two-day march from Belgrade on Thursday, aiming to join a major rally in the country's north this weekend that will mark the anniversary of a deadly train station disaster.

The concrete canopy collapse at the central train station in Novi Sad killed 16 people on Nov. 1. The tragedy has unleashed a youth-led protest movement against autocratic President Aleksandar Vucic.

Protesters believe the victims died because government corruption led to sloppy renovation work at the station. They have been demanding accountability for the disaster, and an early parliamentary election that they hope will oust Vucic's populist government from power.

Flag-waving university students on Thursday led the huge column of marchers setting off on the 90-kilometer (58-mile) journey toward Novi Sad. Saturday's gathering there is expected to draw tens of thousands of people, piling pressure on Vucic.

Various other groups of university students also have been trekking across Serbia for two weeks before they all converge in Novi Sad on Saturday.

Belgrade residents came out of their houses on Thursday to greet the protesters as they passed by. People honked their car horns, waved or blew whistles. Some cried.

Mihajlo Jovanovic, a sports academy student from Belgrade, said that he joined the march because "nothing has changed and we are going there (to Novi Sad) hoping that it finally will change.”

Veterinary student Ana Marija Seslija said that “we are walking to show that our struggle has not stopped and that we are all still active. ”

Authorities have detained scores of university students and other protesters in the past months, trying to crush the resistance. Police have been accused of brutality toward protesters, including beatings and arbitrary detentions.

While 13 people have been charged in the disaster, no trial date has been set. Doubts prevail that proceedings would untangle an alleged top-level corruption web that critics believe led to the fatal negligence and disregard of construction safety rules during the station building renovation.

Vucic, without offering evidence, has branded student-protesters as Western-backed “terrorists,” while the governing Serbian Progressive Party organized counterrallies. This has fueled political tensions.

Serbia is formally seeking to join the European Union. But the accession process has been stalled, because Vucic has nurtured close ties with Russia and China, while being accused of clamping down on democratic freedoms.