SANTA CLARA Cuba (Reuters) - Cuban leaders will not be rushed into decisions about economic reforms and whatever they do will be faithful to the ideals of the Cuban revolution, Vice President Jose Ramon Machado Ventura said on Monday in a nationally televised speech.

The speech was a defiant response to those pushing for faster change on the communist-led island, which is in the grips of a economic crisis.

Machado Ventura, a veteran of the revolution and longtime Castro loyalist, spoke at a celebration marking the 57th anniversary of the start of the revolution that put Fidel Castro in power in 1959.

President Raul Castro was expected to speak, but he was only a spectator at the event and older brother Fidel Castro, who has re-emerged in recent weeks after four years in seclusion, did not attend.

"We will proceed with a sense of responsibility, step by step, at the rhythm we determine, without improvisation or haste so as not to make mistakes," Machado Ventura said to a crowd estimated at 90,000 in the central city of Santa Clara.

"We will continue the study, the analysis and the taking of decisions that lead to overcoming our deficiencies," he said. "We will not conduct ourselves by campaigns of the foreign press."

Machado Ventura spoke in front of a monument holding the remains of Ernesto "Che" Guevara, the Argentine who helped lead the armed insurrection that began on July 26, 1953.

On that day, Fidel Castro led an assault by young rebels on the Moncada military barracks in the eastern city of Santiago de Cuba.

The attack failed, with many of the rebels killed, but it marked the beginning of the end for the government of U.S.-backed dictator Fulgencio Batista, who fled the country on January 1, 1959.

"Today we confirm the commitment with them to be loyal to the ideas for which they gave their lives," Machado Ventura said, referring to those who died in the assault.

NO MISTAKES

Even though President Castro did not speak as he has in past July 26 celebrations, Machado Ventura's words echoed his earlier pronouncements that the government must act deliberately to avoid mistakes that could endanger the future of Cuban communism when the current generation of leaders is gone.

Castro, 79, has tweaked the system to try to create incentives for greater productivity, but his efforts have not yet raised salaries for most Cubans, who receive social benefits but earn on average the equivalent of $18 a month.

Many have said they are eager for improvements, but some people at Monday's event said they agreed with the government's direction.

"Machado made clear that we have to change things, but without anybody interfering. It's a matter for the Cubans and we don't accept pressure from anyone," said Griselda Rodriguez, the head of the agricultural union of the state of Villa Clara.

Machado Ventura, 79, cited three 2008 hurricanes and the longstanding U.S. trade embargo against the island as principal causes for Cuba's current economic lethargy.

Raul Castro surprised many earlier this month by agreeing to release 52 political prisoners in a deal with the Catholic Church that quieted international criticism about Cuba's human rights record.

Machado Ventura did not mention the release of the prisoners, who Cuban leaders view as mercenaries working with the United States to topple the communist government.

There had been expectations that Fidel Castro, 83, might attend the event since he recently reappeared after undergoing intestinal surgery in July 2006.

He has made several appearances covered by state-run media in which he has warned that nuclear war is imminent, sparked by conflict between the United States and Iran.

Fidel Castro ceded power provisionally to his brother at the time of surgery, then officially resigned in February 2008 and Raul Castro was elected his successor by the National Assembly.

Venezuelan President Hugo Chavez was scheduled to speak at Monday's celebration, but canceled his trip due to escalating tensions between Venezuela and neighboring Colombia.