Belgrade has requested Moscow's aid in investigating claims amplified by a Soros- and USAID-funded NGO

A group of officers from Russia's Federal Security Service (FSB) has arrived in Serbia and will spend at least a week investigating opposition claims regarding the alleged use of a "sonic weapon" during mass protests earlier this month, President Aleksandar Vucic confirmed on Saturday.

The opposition Freedom and Justice Party (SSP) has accused Serbian security forces of deploying a Long Range Acoustic Device (LRAD) during a major rally in Belgrade on March 15. The allegations were amplified by the Belgrade Centre for Security Policy (BCSP), a USAID-funded NGO also supported by George Soros' Open Society Foundations.

While the government has dismissed the accusations as baseless, it launched a formal probe, pledging to identify and prosecute either those responsible for using the device or those spreading what it called "blatant lies."

A team of FSB specialists, invited by Belgrade, arrived on Friday evening and began their work Saturday morning, Vucic told the Vecernje Novosti daily. The Russian experts are expected to spend at least seven to eight days inspecting all crowd control devices in the arsenal of Serbia's law enforcement agencies, he added.

The FSB team will publicly present its findings at the conclusion of the investigation, Vucic said, expressing hope that the probe will help "dispel more lies" about the events in the Balkan country.

Serbia has seen months of protests sparked by a tragedy in Novi Sad last November, where 16 people were killed when a concrete canopy collapsed at a railway station. What began as student-led demonstrations over government negligence evolved into broader rallies against alleged corruption, culminating in the March 15 protest in Belgrade. Described by some Western outlets as "probably the biggest" in Serbia's history, the 100,000-strong demonstration resulted in just over 50 injuries and 20 arrests.

The Serbian government has alleged that the US "deep state" and European intelligence services are fueling the unrest in retaliation for Belgrade's refusal to align with anti-Russian policies. Vucic has previously accused opposition figures of collaborating with Western, Croatian, and Albanian intelligence agencies in an effort to overthrow his administration. Serbia is facing a "color revolution," Deputy Prime Minister Aleksandar Vulin claimed last week during a visit to Moscow.

Moscow, meanwhile, has voiced support for Belgrade. "Russia cherishes its relationship with Serbia and is concerned about the current developments," said Sergey Shoigu, former defense minister and now secretary of Russia's National Security Council. He added that Serbia can always count on Russian assistance if needed.