Activists gather at Latin American summit in Panama, US condemns heckling of Cuban dissidents

A man shouts slogans against pro-government supporters from Cuba and Venezuela outside the Vasco Nunes De Balboa Convention Center in Panama City, Wednesday, April 8, 2015. About 100 supporters of Cuba's government aggressively heckled dissidents from the communist-run island attending a civil society forum Wednesday at the start of the Summit of the Americas in Panama. (AP Photo/Ismael Francisco, Cubadebate) (The Associated Press)

A man shouts slogans against Cuban pro-government supporters outside the Vasco Nunes De Balboa Convention Center in Panama City, Wednesday, April 8, 2015. About 100 supporters of Cuba's government aggressively heckled dissidents from the communist-run island attending a civil society forum Wednesday at the start of the Summit of the Americas in Panama. (AP Photo/Cubadebate, Ismael Francisco) (The Associated Press)

Venezuelan Lilian Tintori, wife of jailed opposition leader Leopoldo Lopez, right, and Venezuelan Mitzy Capriles de Ledezma, wife of imprisoned Caracas Mayor Antonio Ledezma gesture an "L" for "libre," or "free" during a press conference in Panama City, Thursday, April 9, 2015. In a document presented at the press conference, about two dozen former leaders of Spain and Latin America critical of the government of Venezuelan President Nicolas Maduro called on the region to put aside "complacent silence" and demand that Venezuela's upcoming parliamentary elections be conducted without political prisoners and with observers, as a possible solution to the South American nation's political crisis. (AP Photo/Arnulfo Franco) (The Associated Press)