Visiting U.S. lawmakers were told by Cuban officials that the ailing Fidel Castro is not terminally ill and will return to public life, but some of the legislators said they saw in the assurances of Castro's health a growing political vacuum on the Communist island.

The 10-member delegation was not allowed to meet with acting President Raul Castro as they had hoped, and lawmakers said his absence was evidence of the political uncertainty created by Cuba's insistence that Castro — who hasn't been seen since late July — will return to power.

"The party line is that Fidel is coming back, which ... creates a sort of vacuum," said Rep. Jane Harman of California.

Castro's medical condition has been a state secret since he underwent surgery for intestinal bleeding in late July and temporarily ceded power to his younger brother Raul Castro. He has not been seen publicly since July 26.

Some U.S. doctors have speculated that Castro could have diverticular disease, which can provoke bleeding in the lower intestine, especially in people over age 60. In severe cases, emergency surgery may be required.

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Rep. Jeff Flake, R-Ariz., said all the Cuban officials they spoke to during the three-day trip that ended Sunday told them the 80-year-old leader's "illness is not cancer, nor is it terminal, and he will be back."

Cuban Vice President Carlos Lage had previously dismissed reports that the leader was suffering from stomach cancer, but officials had not publicly denied rumors that he could have another type of cancer or some other terminal illness.

Castro failed to appear at his own delayed birthday celebrations earlier this month, prompting new speculation that he was on his deathbed.

Raul Castro has appeared increasingly confident in his new role, asserting himself by calling on two occasions for normalized relations and improved dialogue with the United States.

In recent years, the Bush administration has intensified the U.S. trade embargo and other policies aimed at squeezing the island's economy and undermining Cuba's communist leaders.

Bush administration officials have twice rejected offers to talk with Cuban officials since Fidel Castro fell ill, saying that the country must first hold free and competitive elections and release all political prisoners.

Rep. William Delahunt, D-Mass., said, however, the lawmakers' visit "underscores the desire for a change in policy that we believe is embraced by most Americans."

"It's incumbent on us, representing the first branch of our democracy, to come here and to state that we are willing to engage in a sincere and open dialogue, and that everything is on the table," he said.

State Department spokesman Sean McCormack said Friday the lawmakers' trip would have no effect on official U.S. policy toward Cuba.

"This divide over whether or not to have an embargo on Cuba or to lift it, it's a debate that's been going on for some time. We understand that there are some in Congress who have a very different view. As a matter of policy, we of course have an opposite view from the folks that are down there today," he said.

The U.S. lawmakers in Havana said issues of human rights and economic freedom are important to them, but that it is time for the two countries to find creative ways to solve their differences.

"I think this is the golden opportunity (for talks) ... especially as we make a transition in Washington," said Gregory Meeks, D-N.Y., referring to his party's upcoming takeover of Congress. "This should be a dialogue in which we talk to one another, not at one another."

The group of lawmakers arrived Friday and has met with Foreign Minister Felipe Perez Roque, Parliament Speaker Ricardo Alarcon and Basic Industries Minister Yadira Garcia. They had hoped to meet with Raul Castro, but Flake said it was apparently not the right time.

"It seems that the Cuban government may not be ready to say that the new era has begun, and perhaps that meeting would suggest that," said Flake, on his fifth trip to the island.

The lawmakers also did not meet with Cuban dissidents, though delegation members have met with them in the past and will do so again in the future, Flake said.