(AGI) Milan, July 4 - U.S. President Barack Obama has markedthe National Day of the United States at the UniversalExhibition in Milan with a video message. "Hello andcongratulations to Milan Expo 2015," the president said on thespecial day organised on the occasion of July 4, U.S.Independence Day. "It is the anniversary of a promise offreedom and of the future," said the Secretary of Agricultureof the U.S. government, Tom Vilsack. "We are proud to celebrateit at Milan Expo 2015, a place of meeting and dialogue amongnations on the future". To celebrate their National Day, theUnited States selected the "contagious energy" of the TrojanMarching Band of the University of Southern California (USC).The musical students opened the festivities, playing thenational anthems live during the flag raising ceremony at ExpoCentre. The U.S. delegation, led by Mr Vilsack, wasreceived by the sole commissioner for the World Expo in Milan,Giuseppe Sala, by Italy's Minister of Agriculture, Food andForestry, Maurizio Martina, and by the Commissioner General ofExpo 2015, Bruno Pasquino. "The World Expo has focusedpeople's attention on the major challenges facing humanity: theright to food, proper nutrition, climate change," said theAmerican Secretary of Agriculture. "Therefore it is importantto be here, to continue the work we are doing together withItaly and the other countries of the world in view of the UNGeneral Assembly that will determine the post-2015 agenda." Minister Martina underlined the importance of the presence ofthe United States: "Expo Milan 2015, with its great number ofvisitors and international representations, could not dowithout the lively participation of our American friends. Italyhas been working together with the U.S. since preparations forthe exhibition started. Cooperation and dialogue onsustainability, the fight against hunger and the educationaltheme will be the subject of shared strategies in view of COP21 on the Environment and the United Nations Assembly." Theband and cheerleaders of UCS then opened the parade on theDecumano road with music and dance, also involving numerousvisitors on the site. . .