The red, white and blue Cuban flag was raised over the island’s embassy in Washington on Monday for the first time since 1961 — a fluttering symbol of the historic thaw taking place between the Cold War foes.

As pro and anti-Cuban protestors gathered outside the gates of the embassy chanting “Fidel” and “Justice” — the flag was was raised at about 10:35 EST.

The ceremony came after the United States and Cuba reestablished diplomatic ties early Monday after a 54-year gap.

Cuban Foreign Minister Bruno Rodríguez led a delegation of 36 Cuban officials and members of Cuba’s cultural world at the ceremony marking the conversion of its interests section in Washington to a full-fledged embassy.

Speaking at the embassy, Rodríguez hailed the new era in diplomatic relations but said they were just the beginning.

Only if the United States ends the economic embargo on the island, returns the Guantanamo military base and respects Cuba’s sovereignty “will the historic event we are witnessing today make any sense,” he said.

“Today marks an opportunity to begin working to establish new bilateral relations unlike anything that has existed in the past,” he added.

The event is the fruit of 18 months of secret negotiations to restore ties and came around a quarter century after the old Soviet bloc began to unravel and most of the rest of the world experienced rapprochement.

Many in the crowd at the ceremony had worked for decades to lift the U.S. embargo against Cuba and they talked of not wanting to miss the “moment” when the normalization process began.

“Everything that’s happened this whole year, I never thought I’d live to see it,” said Vivian Mannerud, who was among the South Florida guests at the embassy ceremony. “I’m just so used to fighting the battle, fighting the battle,” said Mannerud, a long-time advocate of normalization whose Cuban charter business was firebombed in 2012. There still have been no arrests in the case.

Cuban flag is raised at new embassy in Washington, D.C.

The Cuban embassy in Washington, D.C. reopened on July 20, 2015, after 54 years. Hundreds of onlookers and protestors gathered less than two miles due north from the White House to watch the historic flag raising, the next big step on Obama's ongoing push for better relations with the island country off the coast of Florida. Video is by Brittany Peterson and Ali Rizvi / McClatchy

There was also symmetry and a closing of the loop at the event.

After the United States broke off relations with Cuba, Cuba’s affairs in Washington were handled first by the former Czechoslovakia and then by the Swiss Embassy.

But during an opening toward Cuba by the Carter administration in 1977, both countries decided to staff their interests sections. The first Cuban chief of mission, Ramón Sánchez Parodi, greeted his U.S. counterpart, Wayne Smith, the first U.S. mission chief at the interests section in Havana.

After Smith left his post in 1982, he became a tireless advocate for the normalization process.

“As of July 20, we have diplomatic relations but we still have the embargo and that’s going to be very difficult because it has to go through Congress to be lifted,” Smith said.

The ceremony, however, was not universally embraced.

“For the first time in 54 years, the Cuban flag officially flies in the United States even as Cuba’s Communist government continues with arrests, beatings, and false imprisonments of its people,” Marion Smith, the executive director of the Victims of Communism Foundation, said in a statement. “This is a terrible affront to millions who suffered under Communist governments, and those continuing to suffer under them today.”

Others worried that the deal was lopsided. While the Washington took Havana off the state sponsors of terrorism list, U.S. diplomats in Cuba will remain subject to travel restrictions on the island. In addition, the Castro regime has refused to respect the inviolability of U.S. diplomatic pouches, said Capitol Hill Cubans, a lobbying group.

“Both of these restrictions are in direct contravention of the Vienna Convention on Diplomatic Relations,” the organization said in a statement Monday.

During the flag-raising, as a crowd yelled “Viva Cuba!” a man rushed the embassy gate with sacks of red paint under his shirt. As the bags burst he yelled “this is Cuban blood,” as D.C. police wrestled him to ground and took him away.

Cuba Flag raised at U.S. Department of State

The Cuban flag is raised in the lobby of the U.S. State Department Monday as diplomatic ties resume following decades of hostility between the countries. Video courtesy of the U.S. Department of State

The two women who led the normalization talks between the United States and Cuba, U.S. Assistant Secretary of State for Western Hemisphere Affairs Roberta Jacobson, and Josefina Vidal, who heads the Cuban Foreign Ministry’s United States Department, were also at the Cuban Embassy ceremony.

They faced off against either other across a negotiating table as the two sides hammered out an agreement on how the new embassies will operate. Diplomats from both countries will have greater freedom to travel and engage with the people of each nation.

With embassies in both countries now, “they will be in a stronger position to elevate issues of concern, like human rights, as well as on expanding on areas of cooperation with Cuba,” said James Williams, president of advocacy group Engage Cuba and a guest at the event.

But there are still so many issues that separate the two countries and most acknowledge the hope of any true normalization might be years off.

“We realize that the full normalization of relations between the two countries will be a long and challenging process that will require various actors, including civil society in both countries,” said Tomas Bilbao, executive director of the Cuban Study Group, which advocates for engagement with Cuba.

Very early Monday morning, the Cuban flag was added to the C Street lobby at the State Department where the flags of all the nations with which the United States has diplomatic relations are on display. The United States broke off diplomatic ties with its neighbor in January 1961 after tensions between the two nations had steadily mounted since the 1959 Cuban Revolution.

U.S. Secretary of State John Kerry plans to travel to Havana later this summer to officially mark the debut of the new U.S. Embassy and raise the American flag, but the former U.S. Interests Section, which handled U.S.-Cuban affairs in the absence of diplomatic relations, opened for business as an embassy Monday under rules negotiated in talks between the United States and Cuba earlier this year.

Kerry and Rodríguez were set to talk at the State Department Monday afternoon — the first time there has been such an encounter in Washington between foreign ministers from the two countries in several decades, according to the State Department. It was Rodríguez’s first visit to Washington.

The two men previously sat down together in April at the Summit of the Americas in Panama when President Barack Obama and Cuban leader Raúl Castro also had an historic meeting.

For much of the past half-century, the relationship between Cuba and the United States had been marked by bitterness, bloodshed, separation of families and isolation. A huge exodus of Cubans also reshaped South Florida.

A generation ago, the Cuban-American community might reliably have been expected to greet the news of renewal of diplomatic ties with a Castro still in power with massive and prolonged protests in the streets of Miami.

But in the seven months since a surprise Dec. 17 announcement by Obama and Castro that they were working toward normalizing relations between the two countries and planned to reopen respective embassies, the reaction has been relatively low key.

There have been a few small protests and the Cuban-American Congressional delegation has kept up a steady drumbeat, berating the president for giving up too much in negotiations with the Cubans and not insisting on respect for human rights and civil liberties inside Cuba as a condition for rapprochement. Several members of the delegation will hold a news conference Monday afternoon to reiterate their objections.

Pedro Freyre, a Miami lawyer, attributes the more nuanced reaction to restoration of diplomatic relations to a growing maturity in the Cuban-American community. “I’m so proud of how civil the conversations has been in the Cuban-American tribe,” he said.

Still, Freyre said, many people may have conflicted feelings and it may take them time to process the “irreality” of the new relationship.

“This is not the script I was given as an 11-year-old exile. There was supposed to be a fight that we won,” he said. “But as a 65-year-old man with all that I’ve experienced, I’m glad it happened. It’s the way forward and it’s the right thing to do.”

But Freyre said tensions and hostility bottled up over decades will take a long time to unwind. “It could take years before good things start to happen,” he said. “After all, it’s been five decades. I think new generations — both here and in Cuba — need to come into play. It’s a different matrix now.”

Raúl Castro said last week that now the hard work begins. “A new stage will begin, long and complex, on the road toward normalization, which will require the will to find solutions to problems that have accumulated over more than five decades and hurt ties between our nations and peoples,” he said during a speech before the National Assembly.

Miami Herald South American Correspondent Jim Wyss contributed from Bogotá, Colombia.