But the quiet expansion of Cuba’s military role here has raised a particular concern among critics of Mr. Chávez, who maintain that the military is being retooled — with Cuba’s help — into an institution that can be used to quell any domestic challenge to the president.
In a rare public critique, a former aide to Mr. Chávez has lambasted the role of Cuban advisers in delicate areas that he says include military intelligence, weapons training, strategic planning and the logistics of Mr. Chávez himself, who often travels on a Cuban plane.
“We are at the mercy of meddling in areas of national security by a Cuban regime, which wants Chávez to remain in power because Chávez gives them oil,” the former aide, Antonio Rivero, a brigadier general who retired this year, said in an interview.
“The Cuban advisers are there to exert pressure,” he added, “and they often claim to speak on the president’s behalf as if they were his emissaries.”
Mr. Chávez has made no bones about the presence of Cuban military advisers, who he says are “modestly” helping in some areas. But he has publicly offered no details on how many there are or where they are working.
Carlos A. Romero, a political scientist at the Central University of Venezuela who researches military ties with Cuba, estimates that there are 500 Cuban military advisers in the country, including an elite group of about 20 officers operating from Fuerte Tiuna, the country’s main garrison.
A spokesman at Cuba’s embassy here did not respond to requests for comment.
The critique by General Rivero, who worked as an aide to Mr. Chávez early in his presidency and later as the head of the emergency management agency, comes after years in which Cuba has served as a linchpin of support for Mr. Chávez.
The Cuban doctors have provided free medical care to poor Venezuelans; in exchange for such support, Cuba gets oil imports of about 100,000 barrels a day from Venezuela, helping it recover from an economic collapse after the end of Soviet-era energy subsidies in the 1990s. But the military exchanges have become a delicate issue here.
“Cuba doesn’t sell weapons systems, setting it apart from the military cooperation agreements Venezuela has with Russia or China,” said Rocío San Miguel, a legal scholar here who specializes in military affairs. “What Cuba sells is intelligence and strategic planning, based on 50 years of experience in keeping a repressive regime in power.”
General Rivero, who said he came forward with his criticism “as a matter of sovereignty,” offered no evidence that the military had adopted Cuban-inspired repressive policies. But he said that the Cubans had assumed duties beyond the normal activities of a military alliance, and that their presence in areas like military intelligence could compromise national security.
Mr. Chávez has already taken steps to politicize the armed forces, culling hundreds of officers deemed disloyal and promoting those who support him. He changed the army’s name to the Bolivarian Armed Forces, and at military functions requires soldiers to shout the slogan “Homeland, socialism or death!”
He has grown closer to Cuba as ties to the United States, once the main provider of military advisers to Venezuela, have withered. After Mr. Chávez was briefly removed from power in 2002 by a coup, he halted military cooperation agreements with the United States, which had welcomed his ouster. Since then, Mr. Chávez has also forged defense ties with China, Iran and Russia, and sees those alliances as a counterweight to American power in Latin America.
Some changes in military strategy here already reflect the Cuban model, including an emphasis on preparing for an eventual invasion by the United States; the growth of the Bolivarian militia, an armed civilian force similar to Cuba’s Territorial Militia; and a focus on forging military policy within the Bolivarian Alliance for the Americas, the regional political group led by Venezuela and Cuba.
Mr. Chávez’s supporters describe the ties with Cuba as a natural extension of their compatible ideologies.
“The revolutionary government of Cuba applies a concept of national defense with a prolonged and successful track record,” Pedro Carreño, a former interior minister under Mr. Chávez, wrote in a column in the newspaper El Nacional. “Not having military exchanges with Cuba could be grounds for treason of the homeland.”
Venezuela’s alignment with Cuba differs from the defense policies of moderate leftist countries in the region. Brazil, the region’s rising power, recently signed an agreement aimed at bolstering its military ties with the United States.
For Cuba, a military advisory role abroad is nothing new, even if its activities here differ from the combat brigades sent to Angola and Ethiopia in the 1970s or the advisers in Nicaragua in the 1980s. Cuba’s assistance in Venezuela is much broader, including areas like telecommunications and national identification card systems. The emergence of Cuba as Venezuela’s top ally has led to criticism that the Cubans are helping Mr. Chávez tighten his grip on an array of institutions.
The debate over the alliance comes at a time of rising political tension here. Mr. Chávez is struggling with a sharp economic downturn and spreading public ire over a scandal involving 22,000 tons of imported food found rotting in ports while shortages of basic foods still plague the country.
But even as Mr. Chávez faces these challenges, analysts here say that he has deftly secured loyalty in the armed forces. Days after General Rivero started criticizing the Cuban military presence to private news organizations in April, Mr. Chávez announced that he was raising the pay of the 82,000-strong armed forces by 40 percent.
The state media here, citing a prominent military official, said the pay increase was unrelated to Mr. Rivero’s “lies,” and was aimed at “dignifying” the military’s standard of living.
Mr. Chávez has also made it clear that any rumbling within the military, over Cuban advisers or other issues, would have consequences. He rarely loses a chance to remind other military branches of the growing might of the militia, which has some 300,000 reservists and is designed to operate at his command. At a recent parade of reservists, Mr. Chávez called on them to “sweep away the bourgeoisie” if he were assassinated.
“No one knows better than Chávez himself that Venezuelan history is sprinkled with one military conspiracy after another,” said Fernando Ochoa Antich, who was defense minister when Mr. Chávez attempted his own coup in 1992. “His dependence on Cuba is an effort to improve intelligence controls to prevent a conspiracy from prospering.”