"If we see positive movement then we will respond in a positive way," Obama said.
Castro sarcastically derided the gesture.
"How nice! How intelligent!," Castro said. "So much kindness has not permitted him still to understand that 50 years of blockade and of crimes against our homeland have not been able to break our people."
Castro also blasted Obama for the treatment of five Cuban agents convicted of spying in the United States. Cuba has maintained they have been held unjustly, and strongly objected to the United States' insistence that one of the men, scheduled for release from prison within a year, be forced to serve his probation period of three additional years in the country. Castro said the ruling was unjust but expected.
"Otherwise, the empire would cease to be the empire and Obama would cease to be stupid," Castro wrote.
Cuba has reentered the national spotlight as Republican candidates sparred at last week's debate over resuming charter flights with the nation. Michele Bachmann spoke out strongly against the idea, and later accused Cuba of possibly harboring a Hezbollah terrorist training camp.
“Why would you normalize trading with a country that sponsors terror?” Bachmann said at a rally in Cedar Rapids, Iowa. “There’s reports that have come out that Cuba has been working with another terrorist organization called Hezbollah. And Hezbollah is potentially looking at wanting to be part of missile sites in Iran. And, of course, when you’re 90 miles offshore from Florida, you don’t want to entertain the prospect of hosting bases or sites where Hezbollah could have training camps or perhaps have missile sites or weapons sites in Cuba. This would be foolish.”