Fidel Castro

HAVANA — An ailing, 81-year-old Fidel Castro resigned as Cuba's president today after nearly a half-century in power, saying he will not accept a new term when parliament meets Sunday.

The end of Castro's rule — the longest in the world for a head of government — frees his 76-year-old brother Raul to implement reforms he has hinted at since taking over as acting president when Castro fell ill in July 2006. President Bush said he hopes the resignation signals the beginning of a democratic transition.

"My wishes have always been to discharge my duties to my last breath," Castro wrote in a letter published today in the online edition of the Communist Party daily Granma. But, he wrote, "it would be a betrayal to my conscience to accept a responsibility requiring more mobility and dedication than I am physically able to offer."

In the pre-dawn hours, most Cubans were unaware of Castro's message, and Havana's streets were quiet. It wasn't until 5 a.m., several hours after Castro's message was posted on the Internet, that official radio began reading the missive to early risers.

By sunrise, most people headed to work in Havana seemed to have heard the news, which they appeared to accept without obvious signs of emotion. There were no tears or smiles as Cubans went about their usual business.

"He will continue to be my commander in chief, he will continue to be my president," said Miriam, a 50-year-old boat worker waiting for the bus to Havana port. "But I'm not sad because he isn't leaving, and after 49 years he is finally resting a bit."

Castro temporarily ceded his powers to his brother on July 31, 2006, when he announced that he had undergone intestinal surgery. Since then, the elder Castro has not been seen in public, appearing only sporadically in official photographs and videotapes and publishing dense essays about mostly international themes as his younger brother has consolidated his rule.

There had been widespread speculation about whether Castro would continue as president when the new National Assembly meets Sunday to pick the country's top leadership. Castro has been Cuba's unchallenged leader since 1959 — monarchs excepted, he was the world's longest ruling head of state.

Castro remains a member of parliament and is likely to be elected to the 31-member Council of State on Sunday, though he will no longer be its president. Raul Castro's wife, Vilma Espin, maintained her council seat until her death last year even though she was too sick to attend meetings for many months.

The resignation opens the path for Raul Castro's succession to the presidency, and the full autonomy he has lacked in leading a caretaker government. The younger Castro has raised expectations among Cubans for modest economic and other reforms, stating last year that the country requires unspecified "structural changes" and acknowledging that government wages that average about $19 a month do not satisfy basic needs.

Raul Castro was his brother's constitutionally designated successor and appears to be a shoo-in for the presidential post. More uncertain is who will be chosen as Raul's new successor, although 56-year-old council Vice President Carlos Lage, Cuba's de facto prime minister, is a strong possibility.