PIEDRAS NEGRAS, Mexico - A Roman Catholic bishop in the northern Mexican state of Coahuila on Friday called the first civil union of a lesbian couple "a disgrace."

Karla Lopez and Karina Almaguer, both 29 and of Matamoros, across from Brownsville, Texas, on Wednesday became Mexico's first gay couple to register a civil union, in the Coahuila city of Saltillo.

"This is a disgrace," said Bishop Alonso Garza, of the city of Piedras Negras, across the border from Eagle Pass, Texas. Garza said he lamented that the state had attracted international attention for "this kind of situation."

Coahuila state is the only one of Mexico's 31 states to recognize such unions. In November, Mexico City - which as a semi-independent capital zone has some of the same powers as states - passed a similar measure in November, but it will not take effect until mid-March.

The Coahuila law, which provides gay couples with numerous social benefits similar to those of married couples, was approved by the state legislature Jan. 11 by a vote of 20-13. State Gov. Humberto Moreira later signed the law.

"We have always said we respect (homosexuals') way of thinking, but we are definitely against 'this show,"' Garza said of the news media frenzy stirred up by Lopez and Almaguer's union.

The conservative National Action Party of President Felipe Calderon has joined the Roman Catholic Church in Mexico in strongly criticizing the laws in Coahuila state and Mexico City.