(AP) -- The United States and Cuba have agreed to open embassies in each other's capitals, the biggest tangible step in the countries' historic bid to restore ties after more than a half-century of hostilities.

President Barack Obama is expected to announce the agreement Wednesday at the White House. The U.S. Embassy in Havana is scheduled to open later this month.

The U.S. and Cuba have been negotiating the re-establishment of embassies following a surprise December announcement that secret talks had led to an agreement to restart diplomatic relations.

For Obama, ending the U.S. freeze with Cuba is central to his foreign policy legacy as he nears the end of his presidency. Obama has long touted the value of direct engagement with global foes and has argued that the U.S. embargo on the communist island just 90 miles south of Florida was ineffective.

A senior Obama administration official confirmed the embassy planning. The official insisted on anonymity because the official was not authorized to speak publicly about the matter ahead of the president.

Secretary of State John Kerry, who is in Vienna for nuclear negotiations with Iran, is also expected to speak about the embassy openings. Kerry has said previously that he would travel to Cuba for an embassy opening.

Cuba's Foreign Ministry said Tuesday evening that it would meet with U.S. Interests Section chief Jeffrey DeLaurentis on Wednesday morning to receive a message from Obama about reopening embassies.

The U.S. cut off diplomatic relations with Cuba in 1961 after Fidel Castro's revolution. The U.S. spent decades trying to either actively overthrow the Cuban government or isolate the island, including toughening the economic embargo first imposed by President Dwight D. Eisenhower.

Since the late 1970s, the United States and Cuba have operated diplomatic missions called interests sections in each other's capitals. The missions are technically under the protection of Switzerland, and do not enjoy the same status as embassies.

While the opening of embassies marks a major milestone in the thaw between the U.S. and Cuba, significant issues remain as the countries look to normalize relations. Among them: talks on human rights; demands for compensation for confiscated American properties in Havana and damages to Cuba from the embargo; and possible cooperation on law enforcement, including the touchy topic of U.S. fugitives sheltering in Havana.

Obama also wants Congress to repeal the economic embargo on Cuba, though he faces resistance from Republicans and some Democrats. Those opposed to normalizing relations with Cuba say Obama is prematurely rewarding a regime that engages in serious human rights abuses.

The president also will face strong opposition in Congress to spending any taxpayer dollars on building or refurbishing an embassy in Havana. Congress would have to approve any administration request to spend money on an embassy.

Rep. Ileana Ros-Lehtinen, R-Fla., said in a statement that opening a U.S. embassy in Cuba "will do nothing to help the Cuban people and is just another trivial attempt for President Obama to go legacy shopping."

Sen. Ben Cardin of Maryland, the top Democrat on the Senate Foreign Relations Committee, said the opening of embassies was part of the administration's "common sense approach to Cuba." However, he called for Cuba to recognize that it is out of step with the international community on human rights.

"Arrests and detentions of dissidents must cease and genuine political pluralism is long overdue," Cardin said in a statement.

Obama and Cuban President Raul Castro met in April during a regional summit, marking the first time U.S. and Cuban leaders have met in person since 1958.

For Obama, the embassy announcements come amid what the White House sees as one of the strongest stretches of his second term. He scored major legislative and legal victories last week, with Congress giving him fast-track authority for an Asia-Pacific free trade deal and the Supreme Court upholding a key provision of his health care law.

The court also ruled in favor of gay marriage nationwide, an outcome Obama supported.

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