The United States and Cuba restored full diplomatic relations just after 12 a.m. Monday after more than five decades of hostility.
A few hours later in the pre-dawn quiet, the red, white and blue Cuban flag was hoisted at the U.S. State Department, alongside the flags of the other countries that have diplomatic relations with the U.S.
The U.S. and Cuba each now have a full-fledged embassy in the other's country.
The historic diplomatic shift comes 54 years after a diplomatic break that happened during U.S. President John Kennedy's administration.
*READ: President Obama's Statement on Cuba Policy Changes
Cuban officials, including Foreign Minister Bruno Rodríguez Parrilla, will attend an opening celebration at Cuba's Washington embassy Monday. U.S. Assistant Secretary of State for Western Hemisphere Affairs Roberta Jacobson, who played a key role in the negotiations between the two countries, will also be in attendance.
U.S. Secretary of State John Kerry will formally receive Parrilla Monday. The two officials will hold a joint news conference later in the day.
The opening ceremony for the U.S. embassy in Cuba will be delayed until Kerry can travel to Havana and raise the U.S. flag, but the embassy will be fully functional in the meantime. The State Department says it will operate under the leadership of Charge d'Affairs Jeffrey Delaurentis.
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The re-establishment of ties between the two countries is not without its critics.
Republican U.S. Senator Marco Rubio has said there has not been enough emphasis on Cuba's human rights record. He said earlier this year, "Their view of human rights isn't just different than ours, they are flat-out wrong and immoral in their views."
Roger Noriega, an American Enterprise Institute analyst and a former U.S. ambassador to the Organization of American States, also expressing concern about Cuba's human rights record, said "I think we have had to lower our standards in order to raise our flag in Havana."
Bilateral talks continue
State Department spokesman John Kirby said the U.S. and Cuba continue to have discussions on a wide range of issues.
“We began a conversation that I suspect will continue on human rights, which we know is going to be a part of this new relationship,” said Kirby.
He also said the U.S. and Cuba had agreed to have conversations about fugitives and law enforcement.
The State Department official called Monday’s reopenings a “symbolic step,” but a very important step in the next stage of U.S. relations with Cuba.
The official said a tangible result of the changes is that more Americans would be able to travel to Cuba, and would do so with the support of the U.S. embassy. The official also said Cubans would have increased access to the U.S. embassy in Havana.
In the lead-up to plans to restore ties, the State Department removed Cuba from its State Sponsors of Terrorism list. U.S. officials said the move was separate from efforts to restore relations. However, the designation had been a major sore point for Havana.
Other restrictions under the U.S. trade embargo against Cuba will remain in place. A vote by Congress is required to lift the restrictions.
Long, complex process
In a statement on the Cuban Foreign Ministry website, the Cuban government said the re-establishment of diplomatic ties and opening of embassies “completes the first stage of what will be a long and complex process toward the normalization of bilateral relations.”
The statement also said there could be no “normal” relations between the two countries “as long as the economic, commercial and financial blockage continues to be fully implemented, causing damage and scarcities to the Cuban people.”
However many Cubans have praised their government for enacting the changes and welcome the improved relations with the United States. Some have begun to sport clothing with the U.S. flag and other American symbols.
Pam Dockins contributed to this report
Timeline: US-Cuba Relations