The United States and Cuba have reached agreement on reestablishing diplomatic ties and opening embassies in their respective capitals and the White House is expected to make a formal announcement Wednesday morning, a senior administration official said.

“We expect President [Barack] Obama and Secretary [John] Kerry to address this publicly tomorrow morning,” the official said Tuesday.

The United States and Cuba broke off diplomatic ties on Jan. 3, 1961 after relations progressively worsened after the 1959 Cuban Revolution, and the two countries have spent most of the last five decades locked in an acrimonious relationship that has included the U.S. trade embargo against the island and the failed 1961 Bay of Pigs Invasion.

But on Dec. 17, Obama and Cuban leader Raúl Castro announced a new era of U.S.-Cuba relations. Since then there have been four rounds of U.S.-Cuba talks to pave the way for resumption of diplomatic ties and opening of embassies.

Because the two countries haven’t had formal relations, interests sections in both countries have handled consular affairs and other issues that come up between the two nations. Both interests sections are housed in the former embassy buildings of each country.

The administration must give Congress at least 15 days notification of its intent to open an embassy. Presumably, the clock would start ticking after the president makes his Wednesday announcement.

South Florida Republican Rep. Ileana Ros-Lehtinen said she had heard the reports about an embassy announcement and faulted the State Department for not speaking out more strenuously on human rights violations on the island.

“There was little doubt that the Obama administration would pursue its goal of opening an embassy in Cuba no matter the sad reality on the ground,” she said. “Since Obama's December 17 announcement, the State Department has failed to forcibly condemn the increase of repression on the island now that the Castro regime feels emboldened to continue its attacks against the Cuban people.”

She called opening an American Embassy in Havana “just another trivial attempt for President Obama to go legacy shopping.”

But Sen. Amy Klobuchar, a Democrat from Minnesota, said she welcomed the embassy news: “This is a major step forward, and a necessary step forward.”

Despite strong opposition to the Cuban opening among a bloc of mostly Republican lawmakers, Klobuchar said the administration has the authority it needs.

Klobuchar is a sponsor of bills to lift the trade embargo and to lift all restrictions on travel to Cuba. She said support for both bills is building. “The momentum is on our side, and I do believe it’s going to happen. I just don’t have a crystal ball to tell you when,” Klobuchar said.

McClatchy White House Correspondent Lesley Clark and Washington reporter Chris Adams contributed to this report.