From The White House: On Obama-Castro Handshake

Tuesday, December 10, 2013
Obama's handshake with Cuba's Raul Castro was not planned, the two did no more than exchange greetings, was not a substantive discussion... As the President said, we urge leaders to honor Mandela's struggle for freedom by upholding the basic human rights of their people.
-- Senior Administration Official, The White House, 12/10/13