Florida Senator Marco Rubio has urged Americans to look to the future as he launched his 2016 White House campaign.Mr Rubio, 43, said in a Miami speech he would "lead the way toward a new American century". He presented the presidential election as "a generational choice" and warned against going back to "the leaders and ideas of the past". He is the third Republican to officially announce a candidacy after Senators Rand Paul and Ted Cruz. It comes a day after former Secretary of State Hillary Clinton said she would stand for the Democratic nomination. Referring to her but not by name, Mr Rubio said: "A leader from yesterday began a campaign for president by promising to take us back to yesterday." Mr Rubio, a Cuban-American, has been a harsh critic of President Barack Obama's policies, especially on immigration and the diplomatic thaw with Cuba. He said in his speech that his poor Cuban parents had lived the American Dream but he questioned whether that dream was still possible due to the burden of taxes and regulation.