HAVANA — A U.S. congressional delegation left Cuba on Wednesday after meetings with President Raul Castro and other top officials, but no sign the countries had resolved their latest dispute: the fate of imprisoned U.S. contractor Alan Gross.

Delegation members and their staff said they were encouraged by the relaxed tone of their meetings and indications the Cuban side wanted the dialogue to continue.

Democratic Sen. Patrick Leahy of Vermont canceled a news conference scheduled for Wednesday morning before taking a stroll with his wife in downtown Havana then leaving for Haiti.

"We met with President Raul Castro and discussed the continuing obstacles and the need to improve relations between our two countries," he said in a brief statement.

Leahy said upon arrival in Cuba on Monday that he had spoken with President Barack Obama about the trip and would report back to his administration.

He said the delegation hoped the imprisoned U.S. contractor would fly home with them, but added it was a long shot.

Leahy and Rep. Chris Van Hollen, a Democrat who represents Gross' district in Maryland, visited the American contractor on Tuesday at a Havana military hospital where he is being held, a U.S. diplomat told Reuters.

They had no comment on the visit.

Other members of the delegation included Republican Sen. Jeff Flake of Arizona and Democratic Sens. Debbie Stabenow of Michigan, Sherrod Brown of Ohio, Sheldon Whitehouse of Rhode Island, and Democratic Rep. Jim McGovern of Massachusetts.

Leahy led a similar delegation to Cuba a year ago.

Gross, 63, was arrested in Havana in December 2009 and sentenced to 15 years in prison for installing Internet networks under a secretive U.S. program the Cuban government considers subversive.

The United States insists Gross was merely helping the local population get connected as part of a democracy-building project.

The case halted a brief détente in long-hostile U.S.-Cuba relations that marked the first months of Obama's presidency.

Cuba has linked Gross' fate to that of five Cuban agents imprisoned in the late 1990s for infiltrating Miami exile organizations and U.S. military bases.

The agents, known as the Cuban Five, were sentenced to long terms, ranging from 15 years to life.

They are considered heroes in Cuba, where more than a dozen exile-orchestrated attacks on international tourism facilities occurred in the 1990s.

The U.S. delegation was the first since Obama was re-elected and came just days before Castro was expected to be named for a second term on Sunday.

Castro replaced his ailing brother, Fidel, as president in 2008.

Despite political tensions that have led to the suspension of immigration and other talks, the two leaders have presided over an improvement in people-to-people contact, increased flows of cash remittances from Cuban Americans and continued U.S. food sales for cash.

Between 450,000 and 500,000 Cuban Americans and Americans visited Cuba last year, according to tourism industry sources, and food sales increased by $100 million to $457 million, making the United States one of Cuba's top 10 trading partners and its second-largest provider of tourists after Canada.

This week's visit by the U.S. lawmakers represented the latest failed effort to obtain Gross' release.

Secretary of State John Kerry, when he was a senator from Massachusetts, met with Cuban Foreign Minister Bruno Rodriguez in New York in 2010 to discuss the Gross case, according to Foreign Affairs magazine.

Former President Jimmy Carter also met with Raul Castro on the matter during a visit to Havana in 2011.

The Obama administration has said relations will not improve while Gross remains in custody. Under the 1996 Helms-Burton Act, U.S. sanctions cannot be lifted until Cuba's one-party Communist political system is changed, a demand rejected by the Cuban government.