BELGRADE, Serbia (AP) — The European Court of Human Rights said on Wednesday that Serbia "should prevent the use of sonic weapons or similar devices" for crowd control following claims that a sound cannon was directed at protesters during a huge anti-government rally on March 15.

The court in Strasbourg, France, said its interim measure did not mean it had taken "any position as to whether use of such weapons had occurred” at the demonstration that was part of months-long anti-corruption protests in the Balkan country.

Serbian authorities have repeatedly have denied claims by opposition parties and several experts that a sonic weapon broke a commemorative silence during the March protest causing people to suddenly run in panic while experiencing an array of symptoms and huge discomfort.

The authorities initially said Serbian security agencies did not possess any sonic devices but later admitted they do own several.

The European court said 47 Serbian nationals had filed complaints over the incident while up to 4,000 people reported their experiences in the application collected by a group of Serbian civil society groups. The court rejected requests to investigate the incident or prevent legal proceedings against people who publicly alleged some kind of a device was used.

“Allegedly, the applicants experienced intense instinctive fear, panic, shock, accelerated heartbeat, trembling, hearing problems, vomiting, nausea, tachycardia, and similar symptoms,” a court statement said. “Some allegedly sustained physical injuries due to the panic.”

Footage from the rally show people standing peacefully before a sudden panic erupts and a brief stampede. An Associated Press photographer at the scene said people started scrambling for cover, leaving the middle of the downtown street almost empty as they started falling over each other.

“The State should prevent the use of sonic weapons or similar devices at future protests by the State and/or non-state actors,” the ECHR said. “Any use of sound devices for crowd control (other than for communication purposes) must be prevented in the future.”

The court “noted that use of such weapons for crowd control was unlawful in Serbia and, in particular, potentially serious health effects that could be caused to a large number of persons.”

Protests in Serbia started after a train station canopy collapsed in the northern city of Novi Sad, killing 16 people. Many in Serbia blamed the tragedy on alleged rampant government corruption that fueled disrespect of safety regulations and negligence during the station building renovation.

The protests have developed into a nationwide movement demanding justice for the victims and the rule of law in Serbia, a Balkan nation that is seeking European Union membership but whose populist President Aleksandar Vucic has been accused of stifling democratic freedoms while boosting ties with Russia and China.