That call on Friday and another to Venezuelan President Hugo Chavez the same day constituted the first news in 11 days about the convalescing 80-year-old, who has not been seen in public in more than four months.
Even if Castro is not as sick as some believe — including many in the U.S. government — his prolonged absence from public life have raised questions about whether he will ever return to power.
Chavez said in Caracas on Friday that Castro, a close friend and political ally, called him the same day to congratulate him on his re-election victory earlier this month.
Castro has not been seen in public since July 26, five days before he announced that he had undergone emergency intestinal surgery and was temporarily ceding his powers to his 75-year-old brother, Defense Minister Raul Castro.
The government has occasionally released photographs and videos of Castro since then in an attempt to show that his health is improving. He looked thin and frail in the last videos, released in late October.
The assurances came as members of the U.S. Congress traveled to Havana this weekend seeking improved diplomatic and economic ties with Cuba, anticipating leadership changes in Havana and on Capitol Hill. Ten U.S. congressmen were expected to discuss the possibility of easing U.S. trade and travel sanctions in meetings with Communist officials. They also scheduled talks with Cuba's Roman Catholic Cardinal Jaime Ortega, as well as foreign diplomats, during their trip, which ends Sunday.
Jeff Flake, an Arizona Republican, and William Delahunt, a Massachusetts Democrat, led the group said to be the largest congressional delegation to visit the island since the 1959 Cuban revolution. Both legislators advocate ending decades-old trade and travel sanctions against Cuba.
"This certainly seems like a good time to move ahead," Flake said. "I think that there is more momentum to move ahead than we have had in a while."
The Bush administration, meanwhile, has over the past six years adopted measures aimed at further squeezing the island's economy and undermining Cuba's Communist leaders.
"Members of the Congressional delegation in Cuba are making clear that the new Democrat-led Congress will consider a change in U.S. policy," said CBS News Foreign Affairs Analyst Pamela Falk, who was staff director of the Western Hemipshere subcommittee of the House of Representatives, "but the Cuban government knows as well as anyone that both Democratic and Republican Presidents have resisted any major change in Cuba policy without significant reforms."
The delegation reportedly asked to see Defense Minister Raul Castro, who leads Cuba as his brother Fidel recovers from intestinal surgery. It was not clear Friday if the meeting would take place.
The trip comes amid growing uncertainty about the health of Fidel, the island's 80-year-old leader, who has not been seen in public since he underwent surgery in July. He temporarily ceded his powers to his 75-year-old brother Raul.
Raul Castro has offered to talk with Washington about its differences with Cuba. The Bush administration says there will be no dialogue until Cuba holds free and competitive elections and releases its roughly 300 political prisoners.
"I think that there is a significant majority in the U.S. Congress that believes it is time to engage in dialogue," Delahunt said.
Castro's medical condition is a state secret. Cuban officials insist he is recovering, but U.S. officials say they believe he suffers from some kind of inoperable cancer and will not live through the end of 2007.
Many Castro loyalists were deeply disappointed that he did not appear earlier this month during postponed birthday celebrations attended by more than 1,300 foreign admirers, or at a Dec. 2 military parade marking the 50th anniversary of Cuba's Revolutionary Armed Forces.