The Serbian government is accused of using a sonic weapon against peaceful protesters during a protest in Belgrade.

One protester said she recalled hearing a strange, "unnatural" noise resembling a jet engine, followed by a powerful rush of wind.

Serbian officials denied Sunday that the country's security forces used a military-grade sonic weapon to disperse and scare protesters at a huge anti-government rally in the capital. Rights groups claimed that the widely banned acoustic weapon was used during the protest Saturday.