Migration issues topped the agenda at the latest talks between the US and Cuba, but long-standing disputes threatened efforts to thaw relations between the Cold War enemies.
Cuba repeated its opposition to the United States' so-called wet-foot, dry-foot policy in which Cuban refugees reaching US soil are allowed to stay while those stopped at sea are sent home. Cuba says the policy urges its citizens to try to flee the island.
American officials repeated their call for the immediate release of a USAID worker, Alan Gross, imprisoned in Cuba since December 3 2009. Mr Gross was working on a democracy-building programme when he was arrested and Washington has said there can be no major improvement in relations until he is released.
The migration talks were announced last month after Havana and Washington ended separate negotiations aimed at restarting direct mail service, which has been suspended since 1963. Discussions about migration and mail - along with the relaxation of travel and remittance rules for Cuban Americans - appeared to signal a thaw in chilly relations.
But two recent events - Cuba's support of National Security Agency leaker Edward Snowden's bid for asylum and the seizing of a ship stowed with weapons bound from Cuba to North Korea - now pose new setbacks to warming relations.
Earlier this month, Cuban president Raul Castro threw his support behind other leftist Latin American governments willing to give asylum to Mr Snowden, who has since sought temporary asylum in Russia. Castro did not say whether Cuba would offer him refuge or safe passage, a key issue since Mr Snowden's simplest route to Latin America might be one of five direct flights that Russian carrier Aeroflot operates to Havana each week.
This week, Panamanian authorities seized a ship that had departed Cuba en route to North Korea with a cargo of missiles and other arms hidden under sacks of sugar. Cuba claimed the military equipment was obsolete weaponry from the mid-20th century that it was sending to be repaired in North Korea. The incident underscored concerns about Cuba's relationship with North Korea, which is in a stand-off with the US and its allies for continuing to develop nuclear weapons.
Cuba's delegation to the migration talks said the discussion took place in a "climate of respect" and said it was willing to hold more exchanges in the future.
Marie Harf, deputy spokeswoman at the US State Department, said the discussion focused on the implementation of the 1994 and 1995 US-Cuba Migration accords. The talks are intended to monitor adherence to a 16-year-old agreement under which the US issues 20,000 emigration visas to Cubans each year.
Wednesday's meeting was the first time since January 2011 that the periodic talks had been held.