Castro's comments, in an interview published in the Communist Party's Granma newspaper, also focused on defensive military readiness, which some Cuba watchers took as a stern warning to the island's 11 million people not to cause trouble.
"We have always been disposed to normalize relations on an equal plane," Castro said. "This would be possible only when the United States decides to negotiate with seriousness and is willing to treat us with a spirit of equality, reciprocity and the fullest mutual respect."
In Washington, the U.S. State Department referred to Castro as "Fidel's baby brother," and said the Bush administration was not impressed by his remarks.
The nation's "combat capacity," Castro said, has been boosted with the mobilization of several tens of thousands of reservists and militia members and principal units of regular troops.
Castro took over as acting president after Cuba's longtime leader, Fidel Castro, had emergency surgery last month.