BELEN, Costa Rica (AFP) - Cuban President Raul Castro on Wednesday demanded an end to the US embargo against his country in order to make progress in talks to normalise relations.

"The main problem has not been resolved: the economic, commercial and financial blockade, which causes huge human and economic damage and is a violation of international rights," Mr Castro said.

Speaking at a summit of the Community of Latin American and Caribbean States (Celac) in Costa Rica, Mr Castro said that the road to ending the embargo would be "long and hard".

It was Mr Castro's first public statement since senior US and Cuban officials held landmark talks in Havana last week aimed at reopening embassies and normalising ties.

US President Barack Obama called on Congress last week to put an end to the embargo, which was imposed in 1962 and has been a major source of tension between the Cold War-era rivals since then.

Earlier this month, Mr Obama used his executive powers to ease travel and trade restrictions with Havana, putting a dent on the embargo.

But Mr Castro said that the US leader should do more.

"He could use with resolve his broad executive powers to substantially change the scope of the blockade, even without the Congress decision," he said.

Mr Castro and Mr Obama simultaneously announced on Dec 17 their intention to end half a century of animosity and normalise ties that broke off in 1961.

Some US lawmakers have voiced concern about the rapprochement, especially those of Cuban-American origin, who say Mr Obama conceded too much to Mr Castro without securing guarantees of political change on the island.

"Some forces in the United States will try to abort this process that has started," Mr Castro warned.