CUBA: Leader Fidel Castro's health worsened after he chose risky surgery leading to grave complications, a report claims.

It was reported he rejected a procedure that would have forced him to carry a colostomy bag.

Instead, his chosen operation failed when a suture burst, leaving Mr Castro in a grave condition, according to Spain's El Pais newspaper.

A Cuban diplomat in Madrid said the report was "an invented story."

The paper claimed that after removing an inflamed piece of Mr Castro's large intestine in an operation last year, the doctors connected the remainder directly to his rectum, rather than attaching a colostomy bag.

But then the suture burst, said two medical sources at Gregorio Maranon hospital, Madrid.

Surgeon Jose Luis Garcia Sabrido, who works at the hospital, flew to Cuba in December to treat the 80-year-old.

The surgeon refused to comment on the claims.

In standard colostomies, patients are only dependent on such bags for approximately six weeks.

Attempting to reattach the colon to the rectum is an inherently trickier surgical procedure, since waste from the colon can leak out into the abdomen, causing infection.

"It sounds like they took a gamble and they lost," said Dr Peter Shamanian, an associate professor of surgery at New York University School of Medicine, referring to Castro's surgeons.

"It's always a bad idea to let the patient make the choice," he added.