* Cuba, Mexico said to rediscover 'mutual affection'
* Pemex may take a look at Cuba offshore oil exploration
* Calderon condemns U.S. trade embargo against Cuba
By Jeff Franks
HAVANA, April 12 Mexican President Felipe Calderon declared Mexico and Cuba friends again on Thursday at the end of a visit that included talks with Cuban leader Raul Castro to patch up strained relations between the two countries.
Calderon, speaking to reporters as he prepared to leave Havana for Haiti, said the problems of the past had been replaced by a new cordiality, affirmed by the signing of accords to increase cooperation in areas such as oil and healthcare.
He also condemned the 50-year-long U.S. trade embargo against Cuba.
"Through this official visit, Cuba and Mexico have begun a renewed stage of our relationship," Calderon said at the Havana airport.
"They have been two extraordinary days for Cuba and for Mexico in that their mutual affection has been found again."
Calderon met with President Raul Castro on Wednesday and had what he described as "a frank, open dialogue befitting the leaders of two sister countries."
Both agreed it was time to restore their long friendship even if, as Calderon said on Wednesday, they did not agree on all matters.
"The friendship of Mexicans and Cubans is something that will last forever, beyond any situation," Calderon said. It was not known if he met with former Cuban leader Fidel Castro, who is Raul Castro's older brother and was succeeded by him in 2008.
Mexico once prided itself on having warm relations with Cuba despite the hostility of the United States, its superpower neighbor, toward the island's communist government.
But when conservative Vicente Fox was elected Mexico's president in 2000, he took a less sympathetic line toward Cuba which led to a series of spats with Fidel Castro.
They clashed over human rights, and in 2002 Fox told the revolutionary leader that he could attend a Mexican-hosted diplomatic summit, but had to leave before then-U.S. President George W. Bush arrived.
Fidel Castro recorded the conversation, then made it public in an embarrassing episode for Fox.
Fidel Castro, who is 85 but has a long memory, called Fox a "vile traitor" for the incident in a 2009 column published in Cuba's state-run media.
That same year, Calderon, who succeeded Fox in 2006, angrily cancel led an official visit to Cuba after the island government suspended flights between the two countries at the height of a health scare over swine flu.
Now, said Calderon, both he and Raul Castro had "agreed to increase trade and investment," as well cooperation in health, education, culture and sports.
Trade between the two countries total led $373 million in 2011, the Mexican government said.
Among the accords signed was a non-binding letter of intent for state oil company Pemex to look into "the possibility of participating and investing in the exploration and exploitation of hydrocarbons" in Cuba's part of the Gulf of Mexico contiguous to Mexican waters, Calderon said.
The non-binding nature of the letter of intent means there is no guarantee Pemex will proceed with the evaluation.
"Pemex does not have the capital and/or technology for their own development so I do not see how they would do it in Cuba," said Cuba oil expert Jorge Pinon at the University of Texas.
"If they do it, it would be totally political."
A consortium led by Spanish oil company Repsol YPF is drilling the first of what could be a series of wells in Cuba's part of the Gulf of Mexico, where Cuba says it may have 20 billion barrels of oil.
The U.S. Geological Survey has estimated a more modest 5 billion barrels.
According to Mexican press reports, the two governments were to discuss Cuba's debt of more than $400 million to Mexico, but Calderon did not mention it.
He condemned the U.S. trade embargo and praised Cuba for its role in forming CELAC, the Community of Latin American and Caribbean States, a hemispheric organization created in 2010 that Cuba and its socialist ally Venezuela have promoted as an alternative to the U.S.-dominated Organization of American States.
Calderon flew to Haiti from Havana and was to go to Cartagena, Colombia, for the Summit of the Americas, which the OAS has helped organize.
Cuba, which is a former member of the OAS, was not invited to the hemispheric summit despite a strong push by several left-leaning Latin American countries, led by Ecuador, to have it invited. The United States, which will be represented by President Barack Obama at the event, strongly opposed inviting Cuba.