The US has reopened its embassy in Cuba after being closed for more than five decades, a symbol of warming ties between the two nations.
US Secretary of State John Kerry presided over the ceremony in Havana, and was the first Secretary of State to visit the country in 70 years.
Kerry said the Obama administration wanted to lift the trade embargo on the island, something that the Republican-controlled Congress has blocked.
In an open letter on Thursday, former Cuban leader Fidel Castro said the US owed Cuba millions of dollars because of the 53-year-long embargo.
Kerry described the hoisting of the flag as a "historic moment" speaking during the ceremony on Friday, but he also said that the US would not stop pressing for political change in Cuba.
"The people of Cuba would be best served by a genuine democracy, where people are free to choose their leaders," he said while speaking to onlookers outside the embassy building.
Cuban leader Raul Castro and US President Barack Obama agreed to restore ties in December last year.
While trade and travel restrictions have been relaxed, the Republican-led US Congress has not lifted the trade embargo the US imposed on the communist-run island in 1960.
Cuba says relations will be fully restored only once the embargo is lifted.
