By ANITA SNOW
 Associated Press Writer

 HAVANA -- (AP) -- Cuban President Fidel Castro travels to Mexico this week at a
 sensitive time in relations between the countries, shortly after accusing Mexico of
 acting in U.S. interests and just before conservative President-elect Vicente Fox
 takes office.

 Both Castro and Fox have said that they hope for a friendly relationship between
 their two countries. But the future of those relations is moving into uncharted
 territory.

 The Institutional Revolutionary Party, which ruled Mexico for seven decades and
 which historically was friendly to Cuba, relinquishes the presidential throne to the
 opposition with Fox's inauguration on Friday.

 Fox brings with him a new foreign secretary, Jorge Castaneda, a former Marxist
 academic who has irked Cuba with criticism of the island's human rights
 practices and an unsentimental biography of its revolutionary hero, Ernesto ``Che''
 Guevara.

 Fox, a former rancher and Coca-Cola executive who was candidate of the
 decidedly pro-business, center-right National Action Party, has expressed hopes
 for a democratic transition in Cuba. But he has rejected the U.S. policy of trying
 to isolate the communist island.

 When Fox was governor of the central Mexican state of Guanajuato, he visited
 Cuba and praised the communist government's advances in health and other
 social services, Perez Roque noted. Fox met with Castro during that February
 1999 visit.

 Early this month, Castro made a strong symbolic gesture of friendship to Mexico,
 making a surprise appearance at the unveiling of a new statue of Mexican hero
 Benito Juarez in Havana.

 But on Saturday, the Cuban president made a swipe at Mexico - along with Spain
 and El Salvador - for those countries' support of a motion on terrorism during a
 regional summit in Panama earlier this month.

 Mexico's Foreign Secretariat on Sunday said it would not officially respond to
 Castro's comments ``out of courtesy'' for his trip to Mexico.

 Cuba complained that the motion did not mention of terrorism aimed at the
 communist island. It condemned terrorism in general and acts by the Spanish
 separatist group ETA in particular.

 The motion was seconded by ``a different Mexico,'' Castro complained, a Mexico
 ``now ruled by the interests, the principles and the commitments imposed by the
 (North American) Free Trade Agreement.''

 For decades, Cuba counted Mexico among its closest friends - the only Latin
 American country that refused to break relations with the communist nation after
 the 1959 revolution that brought Castro to power.

 Mexico, located just across the Gulf of Mexico, during those years remained one
 of Cuba's most important trading partners outside the Soviet bloc. It has been a
 leading critic of the U.S. trade embargo on the island.

 The countries' special relationship was based in large part on a shared history of
 often testy relations with their neighbor to the north, the United States.

 Thus, Mexican officials traditionally steered away from criticism of Cuba's political
 and economic systems, instead emphasizing a nation's right to choose its own
 destiny without influence from other countries - especially the United States.

 But that changed a year ago during the Ibero-American Summit of Latin leaders in
 Havana.

 President Ernesto Zedillo did what no Mexican leader had done before - made an
 implicit calls for greater democracy in Cuba.

 ``There cannot be sovereign nations without free men and women,'' Zedillo told the
 summit, ``men and women who can fully exercise their essential freedoms:
 freedom to think and give opinions, freedom to act and participate, freedom to
 dissent, freedom to choose.''

 Zedillo spelled out those freedoms as the ``liberty to think and have opinions,
 liberty to act and participate, liberty to dissent, liberty to choose.''