High-profile trips to China and Italy by Cuban armed forces chief Raul Castro have stoked speculation that he has slowly begun to assume some of the powers of his brother, President Fidel Castro.

``This is raising Raul's profile, giving him a new image -- the image of the man who will follow Fidel,'' said Nicolas Rios, a Cuban-American magazine publisher with good contacts in Havana.

No one in Cuba believes that President Castro will surrender power anytime soon, although the inner working of Havana's leadership is a highly guarded secret.

But Cuba analysts say they are hearing muffled hints of slow and discreet preparations for a transition to a post-Fidel era.

``The word here is that power is being delegated and spaces are being opened for Raul -- and the river is making noise,'' said one Havana man, using a Spanish phrase akin to ``where there's smoke, there's fire.''

Raul, five years younger than his brother, has always been seen as Castro's successor and serves as No. 2 to the three top jobs that his brother holds in the government and the ruling Cuban Communist Party.

Castro himself repeated that Raul was his successor during a speech at a party congress in October in which he said his brother was a good relevo -- a military term for a soldier's replacement at the changing of the guard.

Raul's future has taken on new relevance as Castro, who turned 71 in August, has appeared unusually thin and slow in recent months. While still seemingly capable of delivering marathon seven-hour speeches, he appears to suffer occasionally from serious bouts of health problems.

Rumors that Castro had a pacemaker installed or suffered a slight stroke swept Havana and Miami this summer, but were never confirmed. Cuban officials refuse to comment on Castro's health, saying it is a private matter.

``It doesn't mean Fidel is dying, but Raul's new visibility means that the fact that Fidel will not be there at some point has finally hit home to Cubans,'' said Marifeli Perez-Stable, a Cuba expert at the State University of New York.

Active congress role

Raul played ``a very active role'' in selecting the new members of the Communist Party's inner circle, the Central Committee, at the October congress, Harvard Professor Jorge Dominguez said.

And his No. 2 in the armed forces, Chief of Staff Gen. Ulises Rosales del Toro, was put in charge of the Sugar Ministry, a critical source of hard currency but an industry riddled by bad harvests and inefficiency.

Soon after the congress, Raul left on his first known trip abroad since 1989 -- a two-week visit to China, to learn about its economic reforms.

Raul made an unscheduled stop in Rome on the way back to Cuba and, while never known as an art buff, asked for a private tour of the Vatican's Sistine Chapel. He also met with Pope John Paul II's media spokesman, though both sides insisted they did not discuss the pope's trip to Cuba next month.

More significantly, while Raul was away, the government postponed at least two Cabinet-level meetings on the economy to give him a chance to guide their decisions, said one knowledgeable foreign businessman in Havana.

``This is not Raul usurping power. This is Fidel giving way, saying, `I am beginning to retire. I need to cut back and it's time for you to play some of the roles that I have played,'' Dominguez said.

A new post?

Raul's growing visibility has fueled speculation that Castro may begin to officially surrender some of his power when a new national legislature is elected in February. The National Assembly of People's Power could create a new post of prime minister and thus help Fidel ease out of some of his duties.

``I would bet Castro will initiate a retreat from power, a retirement of sorts, in February,'' Rios said. Similar predictions preceded the Communist Party congress in October, and never materialized.

Cubans tend to view Raul as more pragmatic than his brother, a man who pushed for the creation of farmers' markets and other economic reforms in 1993 as a means for overcoming the crisis sparked by the end of Soviet subsidies.

They also see him as the unquestioned leader of the powerful armed forces, a guarantee of future political stability from a military already so mighty that it is jokingly known as ``Raul's party.''

``It's evident Raul has amassed the kind of apparatus for order that in the short run makes it clear what will happen when Fidel is gone -- Raul follows,'' said Lisandro Perez, head of the Cuban Studies Institute at Florida International University.

Raul may not have it all his way, however. Analysts predict that old-line fidelistas and communist hard-liners may try to curb his power, at least at first.

Harsh diatribe

Analysts have been pointing to an unusually harsh diatribe against free-market economics published by Raul Valdes Vivo, an old-line communist who now heads the party's school for cadres.

Writing recently in the party newspaper Granma, Valdes Vivo seemed to take a slap at Raul's economic pragmatism by charging that Cubans who want to start small enterprises -- one key reform behind China's economic boom -- were little more than capitalist ``piranhas.''

Raul's future also may be clouded by his own health problems, which at age 66 are rumored to include a recurrent liver ailment that raises the question of what might happen if he dies before his older brother.

``There has never been a struggle for power in Cuba because Fidel's successor has always been known,'' said one analyst who asked for anonymity out of fear of angering Havana by speaking on such a sensitive subject.

``But if Raul passes from the scene before Fidel, the door opens for conflicts. In a way, Raul may well be Cuba's key stabilizing factor right now.''