The invention concerns a radio network controller (BSCI), for a radio access communication network, comprising processing means (MT), upon receiving from an alarm center (CA) a message of a first SMS-CB type associated with a selected class of alarm of a selected level, containing an alarm text message addressed to mobile terminals (T) located in at least one selected cell controlled thereby, for interrupting transmission to the mobile terminals, located in each selected cell, of any message of SMS-CB type associated with a class of level lower than that of the selected alarm class, and optionally all other communication of said terminals (for example, telephone calls thereof), so that the first message may be broadcast to the mobile terminals which are located in each selected cell controlled thereby and so that some at least of said mobile terminals should transmit an alarm signal (for example radio) and display the alarm text message contained in the first message.