By Emily Green MEXICO CITY, June 12 (Reuters) - FIFA President Gianni Infantino has failed to deliver on promises to secure full access for the Iranian soccer federation to attend the team's three games in the United States, Iran’s World Cup team supervisor told Reuters. Mahdi Mohammad Nabi, who also served as Iran’s supervisor in charge of squad operations at the 2018 and 2022 World Cups in Russia and Qatar, is among 15 Iranian soccer federation members denied a visa to travel to the U.S. for the World Cup games.