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