Cuban news media on Thursday published the first new writing in months from retired Cuban leader Fidel Castro.

The letter, which was dated Wednesday, comes in the wake of rumors that prompted relatives in both Cuba and Miami to deny that the health of the 86-year-old ex-president was critical.

Castro has not been seen in public since video images showed him greeting a visiting Pope Benedict XVI in late March, and the last of his essays known as "Reflections" was published June 19.

In the letter published by the Communist Party daily Granma, Castro congratulated students of a Cuban medical institute on its 50th anniversary and recalled how just days after it opened in 1962, it was converted into an anti-aircraft installation during the Cuban Missile Crisis.

"In that spirit was born and grew the tradition of that medical institution which, after the most critical days were overcome, was able to forge tens of thousands of professionals and take our country to the highest levels of prevention and health," Castro wrote.

Castro, whose revolution seized power in Cuba in 1959, left office in 2006 due to a life-threatening intestinal condition. His younger brother Raul now serves as president.

However even in retirement and largely out of sight, he continues to cast a long shadow.

Castro's "Reflections," essays and ruminations on everything from international current affairs to the remarkable flexibility of yoga masters, are printed in all state-run newspapers and painstakingly read word-for-word at the top of news broadcasts.

His four-month public silence is not unprecedented, but the rumor mill picked up steam last week after he did not publicly congratulate close ally Hugo Chavez on winning a hard-fought re-election campaign in Venezuela.

Chavez had said just before the vote that he been in touch with Castro.

Late last week, Castro's son and sister both denied that his health was in danger, and state media said a wreath in his name was placed at the final resting place of independence hero Jose Marti on a holiday marking the onset of Cuba's fight to break from Spanish colonial rule.

"These are pure rumors," sister Juanita Castro said from her home in Miami.


Associated Press writer Peter Orsi on Twitter: www.twitter.com/Peter_Orsi