The daughter of Cuba President Raul Castro cannot visit Philadelphia to receive an award for her gay rights activism because the State Department has denied her permission to travel there, officials said Thursday.

Mariela Castro had been expected to attend a conference next week on civil rights for the lesbian, gay, bisexual and transgender communities sponsored by the Equality Forum, according to Malcolm Lazin, the advocacy group's executive director.

"We find it shocking that our State Department would deny freedom of speech, particularly at an international civil rights summit, to anyone, let alone the Cuban president's daughter," Lazin said.

State Department spokesman Noel Clay said he could not comment on the case because visa records are confidential.

Mariela Castro, the niece of retired leader Fidel Castro, is director of Cuba's National Center for Sex Education. As that country's most prominent gay rights activist, she has instituted awareness campaigns, trained police on relations with the LGBT community and has lobbied lawmakers to legalize same-sex unions.

Guillermo Suarez, spokesman for Cuba's United Nations Mission, confirmed that Mariela Castro was in New York on Thursday attending meetings related to the U.N. population conference in Cairo in 1994. She is one of the experts designated by Secretary-General Ban Ki-moon to work on the 20-year follow-up to the action plan adopted in Egypt, Suarez said.

"That's why she asked for the visa and it's the reason for her presence in New York," he said.

Suarez said Castro "doesn't have any personal reaction" to the State Department's denial of her request to travel to Philadelphia.

The State Department bars Cuban diplomats from traveling more than 25 miles from central Manhattan.

The Philadelphia-based Equality Forum sponsors an annual, dayslong international summit on LGBT civil rights. Each year, the event spotlights issues being faced by the LGBT community in a particular nation; this year, the featured nation is Cuba.

Lazin said Castro had agreed to speak on a panel about Cuba on May 4 and was to accept an award for her activism at a dinner that night. He did not expect any visa problems because she had been granted permission to attend an academic conference in San Francisco last year.

However, a number of Cuban-American politicians criticized the State Department for issuing Castro an entry visa for that event. They noted that U.S. rules prohibit Communist Party members and other high-ranking Cuban government officials from entry without special dispensation.

Castro has no official link to the government aside from kinship, although the sex education center is part of Cuba's public health ministry.