Police have also confirmed the incident that two petrol bombs were hurled at the radio station.
The attackers have also torched a motorcycle, Lu 18 Pa 4001, being parked at the premises of the radio station.
Due to fire, the motorbike has been completely destroyed in the incident.
Prior to hurling the bombs at the station, an unidentified man had threatened the radio station over mobile phone for extreme consequences with phone number 9857045894.
Earlier, a group of cadres of agitating Unified Democratic Madhesi Front (UDMF) had repeatedly issued threats to the radio station on the charge of not carrying out adequate news related to UDMF-led Tarai protest.
The local administration has suspected that UDMF cadres might have carried out the act. However, no one has the claim the responsibility so far.
Following the incident, the radio has gone off air for indefinite period citing the security region, said Megh Raj Gautam, Chief Executive Officer of the Radio.