The US flag has been raised over the American embassy in Cuba for the first time in 54 years.
It was the latest symbolic step after the recent diplomatic thawing of relations between the former Cold War-era foes.
US Secretary of State John Kerry said the reopening of the recently restored embassy "is a truly historic moment".
He added: "As we prepare to raise the United States flag here at our embassy in Havana, symbolising the reestablishment of diplomatic relations after 54 years, this is also the first time that a United States Secretary of State has been to Cuba since 1945".
Mr Kerry is also scheduled to meet Cuban dissidents at the US embassyresidence in Havana today. They were not invited to the flag-raising ceremony in deference to the Cuban government, which sees dissidents as US-sponsored mercenaries.
It comes after the two countries formally renewed diplomatic relations and upgraded their diplomatic missions to embassies almost a month ago.
Relations between the two countries had been severed during the Cold War, with the Washington Embassy formally closed in 1961.
Earlier this year, US President Barack Obama and Cuba's President Raul Castro had a historic meeting at a regional summit in Panama signifying a new era in relations.
It was the first time an US president had held a formal meeting with a Cuban leader since Mr Castro's older brother Fidel Castro toppled US-backed dictator Fulgencio Batista in a 1959 revolution.