HAVANA (Reuters) - Cuba released two photographs of Fidel Castro on Sunday in which the ailing leader looked alert as he stood and chatted with visiting Venezuelan President Hugo Chavez.

The pictures, published by the official Juventud Rebelde newspaper, show a gaunt Castro, but with good facial color, in the red, white and blue track suit top that has become his new garb since taking off his olive green uniform and temporarily ceding power to his brother Raul Castro over 14 months ago.

Castro, 81, has undergone at least three major operations in 14 months for undisclosed intestinal problems.

The jacket, in addition to sporting the Cuban colors, has CASTRO, with a Cuban shield below, emblazoned on the left side.

Holding a book about guerrilla fighter Ernesto "Che" Guevara, Castro is shown in the first photograph sitting and chatting with Chavez. In the second picture, Castro and Chavez are standing and shaking hands.

Castro, who has not appeared in public since July 2006, met with Chavez for more than four hours on Saturday, the government said.

Chavez will broadcast his weekly Sunday radio and television show from Santa Clara, Cuba, where Guevara's remains are entombed in a mausoleum. He intends to pay tribute to the Argentine-born Guevara, who helped Castro seize power in Cuba's 1959 revolution and was captured and executed in Bolivia 40 years ago.

Castro is not expected to appear on the show in person.

Castro's long illness has fueled rumors about his imminent death and uncertainty over the political future of the Western Hemisphere's only Communist-run state.

Chavez considers Castro his political mentor and has succeeded the Cuban leader as the main opponent of the United States in Latin America.

His left-wing government has provided Cuba with crucial economic support and oil supplies.