A decision by Secretary of State Hillary Clinton to make an exemption and issue a visa to Mariela Castro, the daughter of Cuban ruler Raul Castro, has drawn irate criticisms from Cuban-American lawmakers and activists.

The visa approval came amid reports by two knowledgeable U.S. officials that Cuban authorities over the past year have increasingly harassed U.S. diplomats in Havana and tightly limited their travels around the communist-ruled island.

Mariela Castro, a sexologist who heads the Cuban National Center for Sex Education in Havana, is expected to participate in the four-day conference of the Latin American Studies Association, which begins Wednesday in San Francisco. Made up largely of U.S. academics, LASA generally invites 20-30 Cubans to its conferences, and a few are usually denied visas.

Sen. Bob Menendez, D-N.J., criticizing the visa for Castro, said she is “a vociferous advocate of the regime and opponent of democracy, who has defended the regime’s brutal repression of democracy activists.”

The U.S. government and LASA should not be “in the business of providing a totalitarian regime, like the one in Cuba, with a platform from which to espouse its twisted rhetoric,” Menendez noted.

Issuing a visa to Castro while Cuban authorities hold U.S. government subcontractor Alan Gross “hostage in a Cuban prison,” only “sends the wrong message to the regime and to Cuba’s struggling opposition movement,” he added.

Menendez also argued that Mariela Castro, a prominent member of the Cuban Communist Party, should have been denied a visa under U.S. regulations that prohibit visitor visas to “officers or employees” of the government or party.

The regulations, however, allow the Secretary of State to make exemptions. Castro is known to have made at least one previous visit to the United States.

It’s difficult to understand why Clinton made an exception for “one of the most vocal defenders of the Castro family dictatorship, who has justified its repressive policies and refers to peaceful pro-democracy activists as “despicable parasites,” wrote Mauricio Claver-Carone, head of the U.S. Cuba Democracy Political Action Committee.

The State Department has not officially confirmed it issued a visa to Castro, and a spokesman on Tuesday would say only that visa records are confidential. She added that there is “no blanket ban on issuing visas to Cuban Government officials.”

Castro’s visit was only one of three that have drawn complaints from Cuban-Americans. Havana historian Eusebio Leal, considered the mayor of old Havana, is giving a presentation Friday in Washington.

And Josefina Vidal, head of the Cuban Foreign Ministry’s North American Department, visited in late April. Her husband was one of 14 Cuban diplomats in Washington and the United Nations expelled in 2003 for spying on U.S. targets.

Obama administration officials have argued that the visa approvals are part of an effort to gain some reciprocity from Havana, although two officials say that Cuban treatment of U.S. diplomats in Havana has worsened in the past year.

Former New Mexico Gov. Bill Richardson, addressing the University of Miami’s Institute for Cuban and Cuban American Studies on April 27, said Cuban authorities had increased their harassment and tightened travel restrictions on U.S. diplomats.

Richardson gave no details but noted that he was briefed by the State Department before he visited Cuba in September to seek Gross’ release. U.S. diplomats, who have served in Havana, say the harassments ranged from slashed car tires to feces left in their homes and attempts to poison their pets.

Another knowledgeable U.S. official said there has been quite a bit of additional harassment of U.S. personnel at the U.S. diplomatic mission in Havana over the last year. Cubans also have increasingly refused requests for routine diplomatic travel, he added.

The official declined to provide additional information and asked for anonymity under U.S. government rules for speaking frankly on sensitive issues.

South Florida Republican Rep. Ileana Ros-Lehtinen called the visa the latest of the “nonstop concessions to the Cuban dictatorship (that) have produced zero results” and asked, “What’s next? Raúl at the White House?”