Cuban leader Raul Castro proposed a secret communications backchannel to the White House, according to WikiLeaks documents published Friday, according to dpa. Castro expressed the idea in 2009 to Spain's then foreign minister Miguel Angel Moratinos, who passed it on to US Secretary of State Hillary Clinton. The confidential US diplomatic cables obtained by the whistleblower website were published by the Spanish daily El Pais. Moratinos suggested that US President Barack Obama and Spanish Prime Minister Jose Luis Rodriguez Zapatero discuss details of such a channel. The affair had already been discussed by Spanish and US diplomats in Havana. The channel would allow Cuba to "make major moves towards meeting US concerns," the Spanish ambassador told a US diplomat. But Washington replied that Havana should "engage seriously through the existing channels" to communicate with the US government. The WikiLeaks cables also reveal US views on the Cuban opposition. US diplomats described opposition groups as often being dominated by individuals with "strong egos," divided and therefore easily manipulated by the Cuban security services. Younger dissidents such as bloggers, musicians and other artists "are much better at taking 'rebellious' stands with greater popular appeal," they observed. However, the most likely immediate successors to the Castro regime will probably come from within the middle ranks of the government itself, the diplomats concluded.