(AP Photo/Javier Galeano)
The Cuban leader commented on Obama to reporters after an event at a Havana medical school for foreigners. He did not elaborate.
Obama has pledged to ease limits on the number of trips Cuban-Americans can make to Cuba and on the money they can send to relatives on the island. He has also offered to negotiate personally with Castro, though he has said he won't push Congress to lift the American trade embargo, at least not right away.
Cubans see those as important steps in improving U.S.-Cuba relations. Obama's predecessor, George W. Bush, tightened sanctions on the communist-governed country
But Obama is receiving a rougher reception in Venezuela after referring to Venezuelan leader Hugo Chavez as "a destructive force in the region" during a recent interview with the Univision television network.
"We are willing to initiate diplomatic discussions about how we can improve relations," Obama said, according to a transcript released by Univision.
But Obama was quoted as adding that he would have "to be very firm that when we see news of Venezuela exporting terrorist activities or supporting militias like the FARC, that creates problems that we cannot accept" a reference to allegations that Chavez's government has backed Colombian rebels who are on a U.S. list of terror groups.
Venezuelan Foreign Minister Nicolas Maduro said he "hopes Obama rectifies" the comments and said the new U.S. president revealed his "total ignorance" about Latin America.
"President Chavez has won 12 of the 14 elections in the past 10 years. He is the legitimate president and his leadership has gone beyond the region and helped solidify the peoples of the world," Maduro was quoted as saying Tuesday on state television, according to the state Bolivarian News Agency.