(ANSA) - BELGRADE, MAR 5 - Sergio Mattarella, the Italian President, has sent a message of congratulations to his Serbian counterpart, Aleksandar Vucic, on his 55th birthday, expressing his hope for further strengthening the two countries' collaborative relations. "Over the years, Belgrade and Rome have developed a friendly and constructive dialogue that contributes to the progress of both our countries," reads Mattarella's message, as announced by the Serbian presidency. (ANSA).