In an essay entitled "You will never have Cuba" published by the Cuban Communist Party's newspaper Granma Monday, Castro stated that U.S. efforts to overthrow him and seize power of the country will never materialize.

The 80-year-old leader reportedly continues to suffer from ill-health and has not been seen in public since last July. His manifesto, however, was signed Sunday afternoon, and he made clear in his statement that Cuba would not only retain its anti-U.S. stance, but it would also continue to follow the communist model of economic growth.

"From one year to the next the standard of living can be improved by raising knowledge, self-esteem and the dignity of people. It will be enough to reduce wastage and the economy will grow," Castro wrote.

But for all his rhetoric about a strong and self-sufficient Cuba, Castro himself has officially ceded power to his brother, Raul, who continues to be the country's acting leader. Meanwhile, Raul's wife, Vilma Espin, died in Havana Monday, the day Castro's manifesto was published, at the age of 77.