Echoing previous statements, he said that no topic was off limits, including American concerns about democracy, freedom of the press and human rights in Cuba, as long as the United States was prepared to hear Cuba’s own complaints. “Any day they want, the table is set,” Mr. Castro said. “This has already been said through diplomatic channels. If they want to talk, we will talk.” The United States and Cuba have not had diplomatic relations for five decades. The State Department said Thursday that before there could be meaningful talks, Havana must institute democratic reforms, respect human rights and release Alan Gross, an American detained in Cuba.