SANTA CLARA (Reuters) - Cuban leader Fidel Castro has questioned U.S. President George W. Bush's mental fitness and rejected as "lies and slanders" recent charges by the American that Cuba encourages sex tourism.

Addressing the nation on the anniversary of his initial guerrilla uprising 51 years ago, Castro portrayed Bush as a dangerous religious fundamentalist bent on destroying Cuban socialism. He accused Bush of exhibiting "strange behaviour and bellicosity."

"Let's hope, in Cuba's case, God does not instruct Mr. Bush to attack our country," Castro said on Monday. "He had better check on any divine belligerent order by consulting the Pope."

In a speech in Tampa on July 16, Bush had accused Castro of welcoming sex tourism, as he courted Cuban-American voters in Florida, a pivotal state in November's election.

Havana strongly denies tolerating sex tourism.

Castro said the accusations were aimed at justifying steps by the Bush administration last month to restrict visits and cash remittances from Cubans in the United States.

"Mr. Bush's lies and slanders and those of his closest advisors were fabricated in a hurry to justify the savage measures taken against Cuban-born people living in the United States who have close family ties in Cuba," Castro said.

Castro quoted extensively from a recent book "Bush on the Couch: Inside the Mind of the President," by Dr. Justin Frank, a Washington psychoanalyst and a Democrat.

The book labels Bush as a "dry-drunk" whose abstinence and strict Christian beliefs make him a rigid leader with paranoid tendencies and a simplistic worldview.

Bush, who gave up drinking in 1986, has acknowledged that he "used to drink too much" but said he did not believe he was addicted.

Castro also quoted from other recent books critical of Bush, including Michael Moore's "Stupid White Men" and "Against All Enemies," by former counterterrorism official Richard Clarke.

The references "help to explain the strange behaviour and bellicosity of the U.S. president," Castro said.

Cuba's communist government was born of a revolution against a corrupt U.S.-backed dictatorship that allowed Mafia-run gaming and prostitution to thrive in Havana in the 1950's. Prostitution was banned, but returned during the severe economic crisis Cuba has undergone since the collapse of Soviet communism.

Castro, who will be 78 on August 13, looked cheerful in his trademark olive-green military fatigues as he handed out awards for revolutionary excellence before his speech at a university theatre in Santa Clara, 176 miles (276 km) east of Havana.