Christian conservative group Family Research Council (FRC) has criticized the start of gay and lesbian weddings in Costa Rica, calling the decision an example of “judicial tyranny.”

The District of Columbia-based FRC is a vocal opponent of LGBT rights and has been outspoken in its opposition to marriage equality in the United States.

Gay couples began marrying in Costa Rica on Tuesday after a ruling striking down the nation's ban on same-sex marriage handed down 18 months ago took effect. In its ruling, the nation's constitutional court said that it was bound by a decision by the Inter-American Court of Human Rights (IACHR) which called for marriage equality in over 20 Latin American countries under its jurisdiction, including Costa Rica.

(Related: Gay couples begin marrying in Costa Rica as ruling takes effect.)

In an email to supporters, FRC said that the decision had been imposed by “judicial tyranny.”

“Although Costa Rica is now the first country in Central America subjected to a re-definition of marriage, the 'conventionality control' doctrine suggests that all 23 of the countries that are parties to the American Convention should comply,” FRC said. “Judicial tyranny marches on.”

FRC has previously said that same-sex marriage hurts children, will lead to God lifting his protection from the United States, and that it “perverts the word love.”