President Hugo Chávez's naming of a heavyweight Cuban official to help fix Venezuela's electricity crisis has fired up his opponents at a politically volatile time for the South American nation.

After days of protests last week in which two male students died, thousands of government and opposition supporters again rallied, the 18th anniversary of a failed coup by Chávez that launched his political career.

The controversial Venezuelan leader said this week that Cuban vice-president Ramiro Valdés, who has been a close ally of Fidel Castro dating back to his 1959 revolution, would head a committee to tackle Venezuela's power shortages.

"The Cubans have had very serious electricity problems," Chávez said. "So here with us to lead this technical commission is one of the heroes of the Cuban revolution."

Power rationing since late 2009 has emerged as a major problem for the OPEC member nation of nearly 29 million people, threatening its ability to pull out of recession and weighing on Chávez's popularity ahead of a September legislative poll.

The government blames a drought and soaring demand for electricity after five years of growth. But the opposition says it is evidence of the incompetence of Chávez's government, which earlier this week celebrated 11 years in power.

Chávez wore a red army beret and drove past hundreds of supporters and soldiers on Thursday at a Caracas military base to mark another anniversary -- 18 years since he tried to take power in a coup that failed but ignited his political career.

'NOT A DAY OF CELEBRATION'

Across town, police blocked hundreds of students from marching to the National Assembly where they had hoped to hand over a proposal to tackle the energy crisis.

"We came to demonstrate and tell the national government that today is not a day of celebration. ... There are many problems and the government is not attending to them," student leader Roderick Navarro said.

The appointment of 77-year-old Valdés, who is also Cuba's information and communications minister, to an electricity committee has incensed Chávez foes. They have long decried the "Cubanization" of Venezuela, accusing the president of ruining their country by trying to copy Castro's communism.

"Now Cuba, which has lived through so many decades of blackouts ... sends us one of their top experts in how to destroy a country," mocked opposition local newspaper.

Opposition leaders complained that Valdés, who was with Fidel Castro when he first took up arms in 1953, had more experience at censoring information than fixing power grids.

Valdés's portfolio, however, includes supervising the Basic Industry ministry, which covers electricity.

Already, thousands of Cubans live and work in Venezuela at the state's invitation, many as doctors and social workers in poor neighbourhoods, others advising the Chavez government. For Chávez die-hards, they symbolize a spirit of cooperation and self-sacrifice that only socialist governments can espouse.

But for the opposition, which is sensing a window of opportunity to cut Chávez's majority in the National Assembly, the Cubans put a face on their worst fears for Venezuela.

Chávez, who recently declared himself a Marxist, loves to taunt his foes, wondering aloud this week if he could extend his 11-year rule to 22 years or even 33. "That would be a bit too long, what do you think?" he said in one speech.

But opposition leaders and students have been having fun at Chávez's expense, too, coming up with one slogan -- "Chávez, you've struck out!" -- that has spread quickly among anti-government circles in the baseball-loving nation.

Most analysts expect Chávez, whose popularity level is hovering around 50 percent, to keep his majority in the September election, though with a reduced number of seats.