The Communist Party dailies Granma and Juventud Rebelde that broke the story still hadn't reached many kiosks, so few Habaneros had read the news before it began to flood the airwaves of the state-owned radio and television stations.

Their first reaction was surprise, and initial disbelief. "It said what?" exclaimed Armando, 69, a carpark attendant in the El Vedado neighbourhood of the Cuban capital, astonished at the news.

With tears in his eyes, Armando nodded his head and said: "He is very ill, it's to be expected." The ailing leader had always said that he would never quit his post while he remained alive, but many Cubans had begun to think that his prolonged absence signalled his withdrawal from power.

Alberto, 32, an administrator, said the 81-year-old leader "must have suffered a relapse". "He's been off a long time," referring to Fidel Castro's 19-month convalescence from a serious intestinal illness suffered in July 2006. But Alberto added: "Make no mistake. Even though he says he's no longer President, he'll keep reading the documents and saying this yes and that no. Fidel will keep on ruling."

There had been signs in recent months hinting that yesterday's announcement was in the air, one Havana-based international commentator observed.

Since December, President Castro has written articles in Granma in which he said he "would never cling to power".

Gustavo, 28, a security guard, said: "I think they made the announcement so they can stop calling Raul Castro first vice-president and second party secretary, and just call him President directly." But, the young man added, even if Raul Castro became President – a development he considered inevitable – Cuba would experience few changes in the short or medium term. "Here things are done at their proper time. Just because Fidel ceases being President, things aren't going to change overnight," Gustavo declared.

But a driver, who said he would rather not give his name, said he found Fidel's resignation "a logical development", necessary to avoid prolonging for any longer the situation in which an interim President has ruled for 18 months. "It was obvious he would resign, and now things will be better."

Cuban radio and television repeated the announcement throughout the day, but without adding any further comment.

Alicia, 44, a private landlady, confessed she didn't usually listen to news programmes. But she thought that President Castro's decision to resign was: "Precise, the right thing at the right time. He's administered the plaster before the wound appears. If he did it today, rather than waiting until next Sunday [when the national congress is to appoint a new ruling cabinet] because he's calculated every move."

"He's not a great economist, he's brought this country to economic ruin," she added. "But as a politician he's a genius." She said she hoped the future would bring "something new because it's necessary, the situation demands it".

Enma, 78, said: "I think the panorama looks very difficult. I'm worried, I'm trembling, because I don't know what changes this new situation will bring. I don't think there's anybody who's more intelligent than Fidel." Alberto, 55, took the news in his stride, and even ventured to suggest that "the announcement that he has resigned doesn't mean that he won't continue".

Among those who heard the news early was Esther, a retired teacher who listens regularly to her favourite station, Radio Marti. "As far as I'm concerned he had effectively already resigned, and I think everything will continue just the same. If he doesn't speak, he'll write," she insisted. "Nothing will change. For the moment, there's no solution."