By ELOY O. AGUILAR
                      Associated Press Writer

                      MONTERREY, Mexico - (AP) -- Cuban President Fidel Castro suddenly withdrew from a U.N. summit and
                      returned home, and Cuban officials indicated someone -- possibly the United States -- had offended the
                      leader.

                      Ricardo Alarcon, president of Cuba's National Assembly, told The Associated Press after Castro's
                      departure Thursday afternoon that Castro left because of ``a situation that for a self-respecting
                      country like Cuba, was unacceptable.''

                      Alarcon, who took Castro's place as head of Cuba's delegation to the U.N. International Conference on
                      Financing for Development, indicated that the incident involved the United States, but would not
                      elaborate.

                      Alarcon wouldn't specify whether the Cuban leader's departure was related to the arrival about 30
                      minutes earlier of President Bush, or whether the United States had exerted pressure to avoid the two
                      running into each other.

                      Bush's national security adviser, Condoleezza Rice, said earlier that Bush and Castro would not cross
                      paths, and Alarcon said: ``She knew why she was saying that.''

                      ''In the final analysis it is a problem with the United States. That doesn't mean that someone from the
                      United States talked to us or asked us to do something,'' Alarcon said.

                      ''We had to say something so people would understand that something had happened, something that
                      forced Cuba to take this decision. We have acted with moderation and in a constructive spirit,'' he said.

                      Castro, who arrived in Monterrey on Wednesday night, addressed the conference Thursday morning,
                      calling the international financial system ''a gigantic casino'' and lashing out at rich nations for blaming
                      poverty on the developing world.

                      ''You can't blame this tragedy on the poor countries. It wasn't they who conquered and looted entire
                      continents for centuries, nor did they establish colonialism, nor did they reintroduce slavery, nor did
                      they create modern imperialism,'' he said. ``They were its victims.''

                      According to a U.S. official who spoke on condition of anonymity, the U.S. delegation had been
                      instructed to leave the designated U.S. seat when it was Castro's turn, and they did. No reporters were
                      allowed into the session, and the television feed showed only the podium.

                      Castro, still addressing the gathered leaders, excused himself and said he had to return immediately to
                      Cuba, citing only ``a special situation created by my participation in this summit.''

                      Mexican officials said they had no idea why Castro was leaving, as did his close friend Venezuelan
                      President Hugo Chavez.

                      ''I really don't know why Fidel is leaving today,'' Chavez said.