Castro has not been seen in public since surgery in July

President Castro - who has temporarily handed power to his brother Raul - is suffering from a serious intestinal infection, the report in El Pais says.

It cites medical sources at a Madrid hospital whose top surgeon travelled to Cuba in December to examine Mr Castro.

In Cuba, there has been no public indication of any deterioration in Mr Castro's condition, correspondents say.

On Monday, an unnamed Latin American diplomat told the Reuters news agency that "Fidel has problems with his stitches healing".

He is reportedly being fed intravenously.

There has been considerable speculation about the health of Cuba's 80-year-old leader since he underwent urgent intestinal surgery in July.

He has not been seen in public since then, and in December he missed a massive military parade in Havana marking 50 years since his return from exile.

In his New Year message, he said he was recovering slowly from the surgery, but said it would be a "long process".

Infections

The report in El Pais, if confirmed, is the first detailed account of Mr Castro's recent health problems.

FAILED OPERATIONS Part of intestine removed - colon connected to rectum Cleaning and draining of infected area Prosthesis implanted Source: El Pais

Diverticulitis Peritonitis

The Cuban leader is said to be suffering from diverticulitis, a condition in which bulges in the walls of the intestine become inflamed and sometimes infected.

According to the Spanish publication, Mr Castro has had surgery on his large intestine three times.

In the first operation - performed after he suffered intestinal bleeding and peritonitis - part of his large intestine was removed and his colon was connected to the rectum to avoid a colostomy.

But this failed and faeces were released into Mr Castro's abdomen, causing another peritonitis.

Mr Castro then underwent a second procedure to clean and drain the infected area. This also failed according to the sources quoted by El Pais, again because the wounds did not heal properly.

A prosthesis was implanted during a third surgical intervention, but it did not work and had to be replaced.

'No change'

El Pais says that when a Spanish surgeon visited in December, Mr Castro had an abdominal wound which was releasing more than half a litre of fluids a day, causing a serious loss of nutrients.

The surgeon, Jose Luis Garcia Sabrido, said at the time the Cuban president did not have cancer, as rumoured, and was making a steady recovery.

On Tuesday, his secretary told the Reuters news agency the doctor had not changed his outlook.

The authorities in Havana have said Mr Castro's health is a state secret, but have rejected speculation that he is suffering from cancer or a terminal illness.