Capitol Hill greeted the news of Fidel Castro’s resignation Tuesday with muted cautiousness, with several members warning that the long-expected ascension of Castro's brother Raul is no cause to celebrate.

“Just because the dictator is now named Raul instead of Fidel, it doesn’t mean that the regime’s repressive rule will automatically change,” said Sen. Robert Menendez (D-N.J.), a child of Cuban immigrants and member of the Cuba Democracy Caucus and Senate Foreign Relations Committee.

“What this move does perhaps present is a moment of hope,” Menendez said in a statement. “Raul does not have the same relationship with the Cuban people as Fidel, and now is the time to challenge him.”

Sen. Bill Nelson (D-Fla.), also a member of the Cuba Democracy Caucus and the only senator serving simultaneously on the Foreign Relations, Armed Services and Intelligence committees, said nothing he has seen or heard indicates Raul Castro is any different from his brother.

"He wants to cling to power. He's as hard-line as Fidel," Nelson said. "It's going to have to be Cuban people who say, 'Enough, we’re tired of this dictatorship.' It's inevitable, just like the people of Eastern Europe threw off the cloak of oppression from the Soviet Union."

Rep. Connie Mack (R-Fla.) said Raul Castro will likely continue dictatorship rule, athough Fidel’s resignation "brings hope that freedom and democracy will once again — and soon — prevail in Cuba.”

Senate and House leaders offered similar reactions.

“Today’s news from Cuba should not focus on one man who is merely formalizing the transfer of power he initiated a year and a half ago,” said Senate Majority Leader Harry Reid (D-Nev.). “It should focus on the more than 11 million Cubans who still seek the freedom they deserve.”

Similarly, Senate Minority Leader Mitch McConnell (R-Ky.) said a second Castro administration "isn't the answer to repression, brutality and fear."

"But that doesn’t diminish the hope for or the efforts toward the day when the Cuban people can choose their own leaders and enjoy the freedom that Castro so relentlessly denied,” McConnell said.

In the House, Speaker Nancy Pelosi (D-Calif.) was the strongest voice of celebration. She called the news "reason to hope that freedom is closer," but added the resignation is "not a guarantee of a democratic future."

“As Cubans at home and those living abroad continue their efforts to create a true democracy in their nation, all of us in the international community should continue to encourage the aspiration of the Cuban people for liberty — the fulfillment of which is long overdue," Pelosi said.

In Florida, GOP Gov. Charlie Crist’s statement also noted that Castro’s resignation may ultimately mean little to hopes for democracy on the island.

“Americans — and Floridians especially — continue to stand in solidarity with the Cuban people as they remain under the oppression of the Castro regime,” he said. “Regrettably, this dictatorship continues through the succession of power to Raul Castro, and as Floridians, we must continue to call for free and democratic elections in Cuba, freedom for all political prisoners and respect for all human rights as detailed in the Geneva Conventions.”

Fidel Castro, 81, resigned in a letter Monday to Cuba's state-run paper, stating, "I will neither aspire to nor accept the positions of President of the State Council and Commander in Chief." The Communist dictator thus ended a nearly 40-year reign over the island country that was somewhat weakened following his July 2006 intestinal surgery, after which he ceded some power to his brother, who was named as Castro's successor.