Cuba was included in the US State Department terror list in 1982, during the tail end of the Cold War, due to Havana's support of leftist guerrilla movements in Latin America. Washington has expressed its willingness to remove the island from the black list, which also includes Iran, Syria and Sudan.

The Organization of American States (OAS) will be holding a summit on April 10-11 in Panama, and both the US and Cuba are expected to attend.

The two countries announced in December they agreed to restore diplomatic ties after more than half a century of animosity.

Machin has said that "resuming diplomatic ties" and "normalizing the bilateral relationship" are two different things.

"If we are going to speak of normalizing ties, the first thing (to do) would be to lift the blockade," he said, referring to the US-led trade embargo against Cuba.