Story highlights "We consider the exchange of ideas useful," Cuban official responds

Pontiff says Mexican drug violence is "idolatry of money that enslaves men"

The pope is making his first visit to Mexico and Cuba

Benedict XVI will visit Cuban cities of Santiago de Cuba and Havana

Responding to Pope Benedict XVI's comment that Marxism "no longer responds to reality," Cuban Foreign Minister Bruno Rodriguez said Friday that his country respects all opinions.

"We consider the exchange of ideas useful," Rodriguez said at Havana's historic Hotel Nacional, adding that his country is perfecting its system.

The pontiff answered reporters' questions about the Caribbean communist island on the papal plane Friday as he began a six-day trip to Mexico and Cuba, according to the Vatican. He arrived in Mexico on Friday afternoon.

"With this visit, a way of cooperation and dialogue has been inaugurated, a long road that requires patience but that leads forward," the pope said, according to the Vatican.

"It is evident today that Marxist ideology as it had been conceived no longer responds to reality," Benedict continued.

"New models must be found, though with patience," the pontiff said.

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He also responded to questions about the role of the church in combating Mexico's drug trafficking violence.

"It is certainly a great responsibility for the Catholic church, in a country in which 80% of the people are Catholic. We must work against this evil, which is destructive of mankind and (especially) of our youth," Benedict said, according to the Vatican.

"The church's great responsibility, therefore, is to educate consciences, to educate in the moral responsibility and to unmask evil, to unmask this idolatry of money that enslaves men; to expose these false promises, lies, deceits, we must see that humanity needs the infinite," the pope said.

Benedict also spoke to how Latin America is celebrating two centuries of independence.

"Naturally, the church must always ask herself whether enough is being done for social justice on this great continent," the pontiff said. "The church is not a political power, not a party but a moral reality, a moral power."

Pope Benedict XVI arrived in the geographic center of Mexico on Friday afternoon, commencing his tour.

The pope arrived in the state of Guanajuato, where he will meet with President Felipe Calderon Hinojosa on Saturday and then preside at Mass on Sunday in the Parque Bicentenario of Leon, Mexico's fourth largest city, the Vatican said.

On Monday, he will depart for Cuba. Benedict XVI will visit Santiago de Cuba and Havana, where Fidel Castro's communist government expelled Catholic church officials after his 1959 revolution. The government did not re-establish formal ties with the Vatican until a visit by Pope John Paul II in 1998.

The pope's visit is to mark the "bicentenary of the independence of the peoples of Latin America; the Mexicans' enthusiastic desire to welcome the Pope; the 20th anniversary of diplomatic relations between Mexico and the Holy See; and the 400th anniversary of the discovery of the image of 'Nuestra Senora de la Caridad del Cobre' in Cuba, with its concomitant Holy Year," a Vatican spokesman said.

The pope's visit to Mexico will be "a journey of hope," Vatican spokesman the Rev. Federico Lombardi said in a statement.

Mexicans are "a people with immense resources and potential, but currently afflicted by serious problems which weigh on their present and future, first among them the problem of violence," Lombardi said, an apparent reference to the carnage caused by drug cartel warfare.

The Vatican also struck a theme of "hope for Cubans" in describing Benedict's journey to the communist nation that had at one time been officially atheist.

Cubans "feel they are on the threshold of what is potentially a new epoch, in which John Paul II's words on the reciprocal openness of Cuba and the world may be realized in a climate of development, freedom and reconciliation," Lombardi said.

Benedict is committed to a "continental mission" in Latin America, launched at the Aparecida Conference, where the church seeks to continue making her "inspirational contribution to the progress of the continent, so that human and Christian values may guarantee integral human development, despite the difficulties and dangers of our time," Lombardi said.