Cuban President Fidel Castro greeted Canada's leader with a searing attack on another country - the United States - suggesting war crimes trials for what he called the "holocaust" of the U.S. embargo of his nation.

Canadian Prime Minister Jean Chretien, who arrived Sunday in Havana, also devoted many of his comments to differences with U.S. policy, though officials with his delegation called Castro's comparison with Nazi genocide "excessive."It is the first time in 24 years that a Canadian leader has visited Cuba. Yet both leaders seemed as concerned with their giant neighbor as they were about one another.

"Through good times and bad, our countries have always chosen dialogue over confrontation, engagement over isolation, ex-change over estrangement," Chretien said, implicitly criticizing U.S. policy toward Cuba.

Chretien is one of the most important Western leaders in years to visit Cuba, adding to a series of Cuban victories over U.S. efforts to isolate the island's communist government.

Castro, dressed in his standard olive-green military uniform, used apocalyptic terms to describe the 36-year-old embargo, which Cubans call a blockade.

"No state should think it has the right to kill another people by hunger and sickness," Castro said. "That is genocide. It is converting a nation into a ghetto and applying a new version of the Holocaust."

He said those who impose the embargo "should be brought before international tribunals and tried as war criminals."

But Castro thanked Canada, "which never has joined the most prolonged, unjust and brutal blockade in history."

The White House defended its stance. In Washington, presidential spokesman Mike McCurry said Monday: "If you needed any more evidence that Fidel Castro is woefully out of touch with history, his remarks welcoming Chretien to Cuba were ample evidence of what an outlier he is in the world community."

McCurry also said the United States has "a very respectful disagreement" with Chretien about how to bring about change in Cuba that does not affect relations between Washington and Ottawa.

Castro and Chretien inaugurated a $40 million terminal at Havana's airport, almost half of it financed by the Canadian gov-ern-ment.

Canada is increasingly important to Cuba's economy: It rivals Italy as Cuba's top tourist market and Canadian companies are major factors in Cuban mining, oil, communications and tourism in-dus-tries.

Chretien defended Canada's policy of "constructive engagement" with Cuba, comparing it with Pope John Paul II's call during his visit in January for Cuba "to open itself to the world" and for "the world to open itself to Cuba."

Canadian officials, like those in many European and Latin American nations, argue that contacts with Cuba are more effective than isolation in promoting changes such as greater respect for human rights.

While Chretien made only a passing reference to human rights, aides speaking on condition of anonymity said he would appeal for the freedom of four prominent dissidents arrested last summer who are being held without trial.

They said it wasn't yet clear if he would meet with other Cuban dissidents.

Cuba has long been one of the most visible points of difference between Canada and the United States. Canada and Mexico were the only countries in the Americas that never cut relations with Cuba.

Several Latin American and Caribbean countries have re-established ties with Havana since the end of the Cold War and of Cuban-backed efforts to foment revolution abroad.

Cuba has helped its image by steadily reducing the number of political prisoners it holds. Human rights activists say there are about 350 political prisoners, down from 1,000 about 16 months ago.

For the first time in several years, the U.N. Human Rights Commission this month refused to condemn Cuba.