Castro thanked the Vatican and Pope Francis for their support in the 'improvement' of relations between Cuba and the US, and the government of Canada for having facilitated the 'high-level' dialogue that Havana and Washington carried on secretly for several months.

"As a result of a dialogue at the highest level, which included a telephone conversation that I had on Wednesday with President Barack Obama, we have been able to make progress in resolving several issues of interest to both nations," Castro said in an address on state television.

The talks led to the release Wednesday of Alan Gross, an American contractor imprisoned in Cuba for five years, as well as the release by the US of the last three imprisoned members of the 'Cuban Five' spying.

Cuba swapped 'a spy of Cuban origin who had been at the service' of Washington for the three spies imprisoned in the US, Castro said. Even though Washington and Havana have agreed to move forward and normalise relations, 'this does not mean that the principal (issue) has been resolved,' Castro said, calling for an end to the US 'economic, trade and financial blockade that causes enormous human and economic damage'.

"Although the blockade measures have been turned into law, the presidente of the United States can modify its implementation by using his executive powers," the Cuban leader said.

Castro acknowledged that the two countries still had huge differences, 'mainly over the areas of national sovereignty, democracy, human rights and foreign policy,' but Cuba's government was 'willing' to have a dialogue on these matters.

"We are proposing to the government of the United States taking mutual measures to improve the bilateral climate and advance toward normalisation of the ties between our countries based on the principles of international law and the United Nations Charter," Castro said.

The Cuban leader called on US in this new atmosphere of dialogue to 'remove the obstacles that prevent or restrict the links between our peoples,' especially those relating to travel, direct mail service and telecommunications.

UN hails restoration of relations between US and Cuba

UN Secretary General Ban Ki-moon on Wednesday heralded restoration of ties between the US and Cuba as 'positive new,' thanking leaders of both countries for 'the very important step'.

"The news is very positive. I would like to thank President Barack Obama of the United States and President Raul Castro of Cuba for taking this very important step towards normalising relations," said Ban at a press conference here.

Ban said that he welcomed Wednesday's development and hoped that the announcement will "help to expand further exchange" between the two peoples who have been separated for quite a long time.

"United Nations stands ready to help both countries and to cultivate their good neighbouring relations," Ban said.

Republicans slam Obama for Cuba decision

The leading Republican in the US House of Representatives on  Wednesday slammed Obama's decision to resume full diplomatic ties with Communist-ruled Cuba as a 'mindless' concession to a dictatorship.

Obama's decision to launch talks aimed at restoring full relations that were severed in 1961 has sparked outrage from House Speaker John Boehner and other Republican members of Congress, which will be entirely GOP-controlled in January.

"Relations with the Castro regime should not be revisited, let alone normalised, until the Cuban people enjoy freedom -- and not one second sooner," Boehner said in a statement issued after Obama announced the policy shift in an address on Wednesday.

"There is no 'new course' here, only another in a long line of mindless concessions to a dictatorship that brutalises its people and schemes with our enemies," Boehner said.

The Speaker, however, expressed "great joy and relief" at the news of the release of US government contractor Alan Gross, who had been imprisoned on the island for five years after being convicted of subversion and was released as part of the process of rapprochement.

In addition, the US freed three Cuban spies from the so-called 'Group of Five' in exchange for a US intelligence agent imprisoned in Cuba for nearly 20 years.

The major policy shift, however, will not bring a swift end to the United States' longstanding economic embargo of the island, which will require congressional approval.

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