Both Morales and Hugo Chavez, the Venezuelan leader, have expressed hope that Barack Obama, the US president-elect, will remove the embargo on Cuba.
On Tuesday, leaders attending the Mercosur summit in the resort town of Costa Do Sauipe also issued a special statement demanding an end to the US sanctions which have been imposed on Cuba since 1962.
The regional meeting, aimed at solidifying South American unity, includes senior officials from 33 countries including Raul Castro, the Cuban president, on his first foreign tour abroad.
Al Jazeera's Lucia Newman at the summit in Brazil said that Latin American leaders were being more vocal in their criticisms of the US embargo than they had been for many years.
|Raul Castro said he was in 'no hurry' to
mend US diplomatic relations [AFP]
Speaking on Tuesday, Raul Castro, the Cuban president, said that leaders at the Mercosur summit had supported a request to demand the US "cease this illegal and unjust political violation of the human rights of our people".
Castro said in his speech to the other leaders that regional integration was needed in Latin America to help it advance against what he said was the failure of US-backed policies.
Castro, 77, took over as Cuban leader from his brother, Fidel, in February.
The summit is the largest in the Western hemisphere to exclude US representation and has been hailed as a sign that Latin America is demanding a new independence from Washington.
"The presence of Cuba is a very strong signal that America is no longer the boss in Latin America," Hugo Chavez, the Venezuelan president, said as he arrived.
On Monday, Castro told Al Jazeera that the US must make concessions first if the two countries are ever to restore diplomatic ties severed for more than 40 years.
Reports say Luiz Inacio Lula da Silva, the Brazilian president, could mediate between Washington and Havana.
Castro, said the "era of unilateral concessions was over", and insisted that Cuba had only ever defended itself against the US.
"We have never hurt the United States, we have only defended ourselves. We are the ones who have been hurt so we are not the ones who have to make a gesture. Let them do it," he said on Monday.
The Cuban leader said he was in "no hurry" to mend diplomatic relations with the US, which were severed in 1961, following the overthrow of the US-backed government by Fidel's revolutionary movement.
"More than 70 per cent of Cubans were born under the blockade which has been in place for almost 50 years," Castro said.
"I'm 77-years old but I feel good and young. In other words, if this doesn't get resolved now, we'll wait another 50 years."