On March 15, 2025, a large-scale protest titled '15 for 15' took place in Belgrade, attracting participants from across Serbia, including a notable presence of students who had marched for days to reach the capital.

The event was marked by significant turnout estimates—107,000 according to police reports and between 275,000 and 325,000 according to the Archive of Public Gatherings.

The protest culminated in a moment of silence that ended abruptly amid chaotic scenes triggered by a sudden, loud noise of unclear origin, which witnesses described as causing panic and a 'stampede' among attendees.

Initial reactions from student representatives, opposition leaders, and civil society organizations suggested that a 'sound cannon' or some unidentified sonic weapon had been deployed, a claim vehemently denied by government officials.

Authorities asserted that they had not used such a device, labeling those spreading rumors about its existence as purveyors of falsehoods.

Amid the unrest, the expanded Rector's Collegium of the University of Belgrade, alongside civil organizations and student bodies, called for an independent investigation into the source of the noise that disrupted the gathering.

In contrast, the UKCS Emergency Center denied reports of patients being treated for symptoms linked to the alleged use of a 'sound cannon'.

However, testimonies from individuals who attended the protest suggested widespread discomfort, including symptoms such as nausea, dizziness, and headaches, leading them to seek medical assistance at local health facilities.

Following the protest, students organized another gathering outside the Ministry of Health, demanding transparency regarding the number of individuals who sought help after the chaotic event and accountability for healthcare professionals accused of neglecting patients.

This second demonstration concluded peacefully, punctuated by slogans critical of Health Minister Zlatibor Lončar and calls for continued resistance.

As the situation evolved, the Commissioner for Citizens' Protection, Zoran Pašalić, announced an investigation into the allegations of unlawful use of sonic weapons during the March 15 protests and requested relevant information from both the Ministries of Internal Affairs and Defense.

Additionally, the Higher Public Prosecutor's Office in Belgrade began proceedings to identify those disseminating false information regarding the protest.

The Security Information Agency (BIA) issued a statement categorically denying the use of a sound cannon, claiming no such device was observed among law enforcement during the protest.

The agency emphasized that the accusations were unfounded and called them outrageous fabrications.

Participation in the protests remains significant, as evidenced by the formation of a petition demanding a United Nations investigation into the alleged use of a sound cannon, which has gathered over 410,000 signatures from around the world within a few days.

Meanwhile, the Green-Left Front announced they would provide free legal assistance to anyone affected by the purported use of unlawful sonic weapons.

In a separate incident, protests continued in Obrenovac where local government officials were confronted by citizens expressing anger over a video showing them leaving Pionir Park during student protests.

Additional demonstrations have emerged across various cities in response to the unrest in Belgrade.

Amidst these developments, President Aleksandar Vučić dismissed claims regarding the sound cannon as fabrications while indicating the government’s willingness to cooperate with both the FBI and Russian intelligence for an independent investigation into the matter.

The political climate remains tense, with continued demands for accountability from both student-led movements and various political factions.