US President Barack Obama met his Cuban counterpart Raul Castro on Tuesday at the United Nations - all smiles after both renewed their calls for an end to the US trade embargo against Havana.

The leaders of the former Cold War rivals shook hands at the start of what was their second meeting, after an historic encounter in April at the Summit of the Americas in Panama.

Close neighbors but long-time foes, the United States and Cuba restored diplomatic ties in July after a five-decade stand-off, and now must turn their attention to economic relations.

The two countries have reopened their embassies in each other's capitals and are engaged in a dialogue to resolve their remaining political differences, but US trade sanctions remain.

Obama's White House wants to lift the embargo, which prevents almost all trade across the Florida Straits, but conservatives in the US Congress are not ready to forgive the communist island.

After the meeting, the White House said the leaders had discussed the visit to both countries last week of Pope Francis, who helped mediate closer US-Cuba ties.

Obama said, recent US regulatory changes that did not need Congressional approval would allow more Americans to travel and do business in Cuba.

On Monday, during a speech to the UN General Assembly, Obama said he was confident Congress would "inevitably lift an embargo that should not be in place anymore."

"For 50 years, the US pursued a Cuba policy that failed to improve the lives of the Cuban people," he admitted, to applause, in his address to fellow world leaders.

"We changed that. We continue to have differences with the Cuban government. But we address these issues through diplomatic relations, and increased commerce, and people-to-people ties."

Castro, the 84-year-old veteran revolutionary who succeeded his brother Fidel in 2006, said normal relations" will only be achieved with the end of the economic, commercial and financial blockade".

"Change won't come overnight to Cuba," Obama said, "but I'm confident that openness, not coercion, will support the reforms and better the life the Cuban people deserve."

Agence France-Presse