CARACAS - Venezuela's Hugo Chavez and Cuba's Raul Castro - two presidents who need each other but for different reasons - signed a series of bilateral accords here Saturday in a visit heavy with symbolism because it marked the first trip abroad by Castro since he succeeded his ailing brother Fidel.

''We give a fervent welcome to you as one of the forces behind the [Cuban] Revolution," Chavez said, as he greeted Raul Castro with a hug at the international airport outside Caracas. "It's a great honor for us to receive you."

"I bring a salute, a hug for all Venezuelans from the Cuban people and from the leader of the revolution, Fidel Castro," Raul Castro replied.

Speaking to reporters a few minutes later, Castro remarked that he had last visited Venezuela 55 years ago, when he was a student conspiring with his older brother to overthrow Cuba's dictatorship.

Raul Castro said he offered his respects then to Simon Bolivar, the Venezuelan who played a decisive role in freeing South America from colonial Spain nearly 200 years ago. Chavez constantly cites Bolivar as a role model.

So it was not surprising that the two presidents laid a wreath at a statue of Bolivar in downtown Caracas in the morning and at Bolivar's tomb in the afternoon.

For Raul Castro, the trip was important for more than just the symbolism: Cuba's economy depends on Venezuelan oil that Chavez is believed to provide for free.

For Chavez, the trip was important for its imagery: it reinforced his ties to the Cuban Revolution and Fidel Castro that serve as the guiding stars in his efforts to forge an anti-U.S. and anti-capitalist alliance throughout Latin America.

Outside commentators have speculated that Chavez has been unable to establish with Raul Castro anything near the warm and indeed fatherly relationship that he has enjoyed with Fidel Castro, who relinquished power in July 2006.

To perhaps show otherwise Saturday, Chavez hugged Raul Castro upon his arrival and draped his arm around him repeatedly as if they were best friends.

But Daniel Erikson, a senior fellow at the Inter-American Dialogue and author of the recently published book "The Cuba Wars" said that the question of personal chemistry between Chavez and Raul Castro takes a back seat to their mutual needs.

"Venezuelan oil has kept Cuba running the past few years," Erikson said.

Besides wanting to link himself to Cuba and the Castros, Chavez benefits from the thousands of doctors, nurses, sports coaches and agricultural specialists who serve Venezuela's poor, Erikson said.

Jorge Pinon, a Cuban native who is the energy fellow at the University of Miami's Center for Hemispheric Policy, said the 94,000 to 96,000 barrels per day of crude oil, diesel and jet fuel that Venezuela sends to Cuba amount to two-thirds of the petroleum products that the island nation consumes. It will be worth at least $3 billion in 2008, Pinon said.

"If Chavez gets hit by a truck tomorrow, Cuba is in big trouble," he said.

Apparently with that in mind, Raul Castro last month hosted Russian President Dmitry Medvedev and senior officials from the state oil company, Gazprom.

Cuba's foreign minister traveled to oil-rich Angola this year.

Raul Castro has also hosted two visits in 2008 from Brazilian President Luiz Inacio Lula da Silva and invited Brazil's powerhouse state oil company, Petrobras, to drill for oil offshore from Cuba.

Raul Castro is traveling to Brazil for a two-day meeting that begins Tuesday of Latin American and Caribbean leaders. He will remain for a state visit in Brazil.

"Castro realizes that Cuba's Achilles Heel is Venezuela," Pinon said. "He's asking: What's Plan B?"

A "Plan B" that didn't involve Venezuela would be devastating to Chavez, who has cast himself as the political heir of Fidel Castro. Chavez travels frequently to Cuba to visit the ailing former leader and typically calls out "How are you, Fidel"? in English on his Sunday nationwide chats.

Raul Castro suggested in remarks last month that Chavez pressured him to visit Venezuela before he went to Brazil.

For his part, Chavez had emphasized in recent days that Fidel Castro also made his first foreign trip abroad to Venezuela after assuming power, nearly 50 years ago, immediately after the Cuban Revolution triumphed.

Oil played a key role on that trip, too, but behind the scenes.

Some 20,000 delirious Venezuelans greeted Fidel Castro at the airport and thousands more turned out for a massive rally in downtown Caracas.

Fidel Castro said he came to Venezuela to thank President-Elect Romulo Betancourt for supporting the Cuban Revolution.

But Betancourt disclosed later that Castro asked him for a $300 million loan to help Cuba end its dependence on the United States, wrote Robert Quirk in his 1993 biography, "Fidel Castro." Venezuela could make the payment in oil, Castro suggested.

Betancourt rebuffed him. Castro retaliated by sponsoring a guerrilla movement in Venezuela that attempted but failed to topple Venezuela's democracy.

Raul Castro's visit reflects the sharply different panorama today.

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