U.S. President Barack Obama and Cuban President Raul Castro will have a substantive 'discussion' tomorrow at a regional summit the two men are attending this weekend in Panama, the White House said Friday. It will be the first time in more than 50 years that leaders from the previously estranged countries will have had a lengthy in-person exchange. Ahead of an anticipated run-in, if not a formal meeting, this weekend in at the seventh Summit of the Americas, the two presidents spoke by phone on Wednesday for only the second, known time in as many years. Jorge Leganoa, deputy director of Cuba's National Information Agency, this morning made the disclosure to the Associated Press, and a White House official later told reporters traveling with the administration, 'I can confirm that President Obama spoke with President Castro on Wednesday, before President Obama departed Washington.' Scroll down for video . President Barack Obama walks across the Miraflores Locks during his tour of the Panama Canal today. Obama is in Panama to attend the VII Summit of the Americas. He and Cuban President Raul Castro spoke on the phone Wednesday ahead of an anticipated 'interaction' at the conference . Cuban President Raul Castro, second left, arrives in Panama City. A White House official today told reporters traveling with the administration: 'I can confirm that President Obama spoke with President Castro on Wednesday, before President Obama departed Washington' Apart from a couple of brief, informal encounters, including a 2013 handshake between Obama and Castro at South African leader Nelson Mandela's funeral, the leaders of the United States and Cuba have not had any significant meetings since Cuba's 1959 revolution . President Barack Obama is pictured here today with Secretary of State John Kerry, left, and National Security Adviser Susan Rice, far left, at a bilateral meeting with Panamanian President Juan Carlos Varela, who is out of frame . The decades-long detente between the countries appeared to be official over on Friday as the United States' Obama and Cuba's Castro prepared to share the same stage  in an encounter rich with symbolism as their countries . set aside decades of mistrust and attempt to restore diplomatic . relations. The rapprochement is set to dominate the Summit of the . Americas meeting, held in Panama, less than four months after . they announced they would seek to lower tensions and boost trade . and travel between the two Cold War enemies. Obama and Castro have separate agendas for most of the day, and the White House had said a private meeting was not on the books. But they were both scheduled to attend the start of the summit along with . other regional leaders on Friday evening and the White House said they could have an unscripted 'interaction' there. A national security adviser to the president told reporters in a Friday update, 'We don't have a formal meeting scheduled at a certain time, but we anticipate they will have a discussion tomorrow.' 'We certainly do anticipate that they will have the opportunity to see each other at the summit tomorrow, to have a discussion,' the adviser, Ben Rhodes, reportedly said. Apart from a couple of brief, informal encounters, including a 2013 handshake between Obama and Castro at South African leader Nelson Mandela's funeral, the . leaders of the United States and Cuba have not had any . significant meetings since Castro's older brother Fidel toppled U.S.-backed dictator Fulgencio Batista in a 1959 . revolution. But the two nations' top diplomats - Secretary of State John . Kerry and Cuban Foreign Minister Bruno Rodriguez - held talks at . a Panama City hotel on Thursday night, the first meeting of its . kind since John Foster Dulles and Gonzalo Guell got together in . Washington in 1958. Sitting face-to-face in a room visible through a large glass . window, Kerry and Rodriguez talked for over two hours. A senior . State Department official described it as a 'lengthy and very . constructive discussion' and said they made progress. Obama and Castro have separate agendas for most of the day, and the White House had said a private meeting was not on the books. But they were both scheduled to attend the start of the summit along with other regional leaders on Friday evening and the White House said they could have an unscripted conversation there. By Friday afternoon that exchange had been upgraded by the White House to a 'discussion' Secretary of State John Kerry and Cuban Foreign Minister Bruno Rodriguez - held talks at a Panama City hotel on Thursday night, the first meeting between the countries' diplomats since 1958 . President Obama,  John Kerry and Guatemalan President Otto Perez Molina participate in a multi-lateral meeting with Central American Integration System (SICA) Presidents this afternoon . Obama appears to be close to removing Cuba from the U.S. list of countries that it says sponsor terrorism. Cuba's . inclusion on the list has exacerbated tensions and made it . harder for U.S. firms to do business with Cuba. The U.S. State Department has now recommended that Cuba be . taken off the list, a U.S. Senate Foreign Relations Committee . aide said on Thursday. Obama is expected to agree, although it is not clear whether . he will announce his decision during the summit. 'We don't want to be imprisoned by the past,' Obama said Thursday during the first leg of his trip abroad in in Jamaica. 'When something doesn't work for 50 years, you don't just keep on doing it. 'You try something new.' Rhodes told reporters Friday that he was 'not ruling out any announcement but... we are not there yet in terms of a final recommendation being made to the president, and the president making a determination.' A U.S. official said Kerry and Rodriguez used their meeting . to smooth the way for Cuba's removal from the list. The United . States has pushed for Cuban assurances of no future support for . terrorism, and Cuba has made the same demand of Washington. Striking Cuba from the list would move the two countries . closer to renewing full diplomatic relations, broken off by . Washington in 1961, and would be popular in Latin America, where . governments had pushed Washington for years to change its Cuba . policy. Panama's President Juan Carlos Varelam center right, Obama smile at the signing of an agreement for the Panamanian airline Copa to buy  total of 61 Boeing aircraft.  Also pictured is Copa Airlines President, Stanley Motta (back), and CEO of Copa Airlines, Pedro Heilbron, right . Widespread praise in the region for Obama's new Cuba policy . was tempered last month, however, when his administration . imposed sanctions on Venezuela, Cuba's closest ally and main . benefactor. That controversy now hangs over the summit, which . ends on Saturday. Venezuelan President Nicolas Maduro says he will present . Obama with a petition signed by 13.4 million people demanding . that the sanctions be reversed. He is certain to receive support . from Castro and other left-wing leaders in Latin America. Of the situation, Rhodes on Friday said, 'Our principal way of communicating with Venezuela will be direct dialogue, even as we know that there will be differences between our two governments on a variety of issues.' Following Friday's announcement that President Obama would in fact meet with Castro, South Carolina Senator Lindsey Graham, increasingly a thorn in the administration's side, said the U.S. president 'is truly writing new chapters in American foreign policy' - but they are 'ones of America and the values we stand for – human rights, freedom, and democracy – in retreat and decline.' Graham accused Obama of appeasing 'autocratic dictators, thugs, and adversaries and said he has 'emboldened' America's enemies while leaving the country's 'friends demoralized.' 'There can be no doubt that President Obama’s failing foreign policy has greatly diminished America’s influence in the world,' the Republican lawmaker who is 'testing the waters' for a presidential campaign said. President Obama reacts as Jamaica's Prime Minister Portia Simpson Miller, second left, insists on standing next to him after moving aside Bahamas Prime Minister Perry Christie, left, as Obama joins a meeting of the leaders of CARICOM, the Caribbean Community nations, at the University of the West Indies in Kingston on Thursday, the first leg of his trip abroad .
Ahead of an anticipated run-in this weekend in at the seventh Summit of the Americas, the two presidents spoke by phone on Wednesday . The two nations' top diplomats held talks at a Panama City hotel on Thursday night, the first meeting of its kind in as many years . White House had said a private meeting was not on the books but they could have an unscripted 'interaction' on the sidelines of the event . Adviser to Obama said Friday: 'We don't have a formal meeting scheduled at a certain time, but we anticipate they will have a discussion tomorrow' U.S. State Department has now recommended that Cuba betaken off the list of countries that sponsor terrorism - Obama is likely to approve .