"Every time we get a notification like that we take it very seriously and we don't want to take any risk," a spokesperson at the Ghent prosecution office told Reuters, adding that police were currently checking the bus, its 46 passengers and their luggage.
She declined to disclose any details on the suspects as well as on the content of their conversation.
Belgium is on heightened alert after Islamic State claimed responsibility for an attack that killed two in Brussels in October.
(Reporting by Tassilo Hummel; Editing by Sudip Kar-Gupta)
