WASHINGTON (AP) — Migration issues are headlining talks in Washington between the U.S. and Cuba, yet long-standing disputes threaten efforts to thaw relations between the Cold War enemies.

On Wednesday, Cuba repeated its opposition to the United States' so-called wet-foot, dry-foot policy in which Cuban refugees reaching American soil are allowed to stay while those stopped at sea are sent home.

American officials reiterated their call for the immediate release of a USAID worker, Alan Gross, imprisoned in Cuba since Dec. 3, 2009.

Last month, Havana and Washington wrapped up separate talks aimed at restarting direct mail service. But Cuba's backing of National Security Agency leaker Edward Snowden's bid for asylum and the seizing of a ship with weapons bound from Cuba to North Korea pose new setbacks to relations.