By Alice Scarsi & Charlie Duffield Serbian President Aleksandar Vucic has prompted concern after making a stark comment regarding the future of his country. Posting on social media on Tuesday, Mr Vucic caused alarm bells in response to an unspecified threat about both his country and the ethnically Serb Republika Srpska region of Bosnia, the Daily Express reports. The politician wrote on Facebook: “Difficult days are ahead of Serbia. At this moment, it is not easy to say what kind of news we have received in the last 48 hours, [but] they directly threaten our vital national interests, both of …