COEUR D'ALENE, Idaho (AP) — A Christian religious rights legal organization has filed a federal lawsuit against a northern Idaho city contending its anti-discrimination ordinance compels a wedding chapel to perform same-sex marriages.

The Coeur d'Alene Press reports that Coeur d'Alene City Attorney Mike Gridley in a letter on Monday to the Alliance Defending Freedom says that because the wedding chapel is registered as a for-profit business, it would likely be violating city code if it turned away same-sex couples.

The lawsuit filed Friday contends the city's anti-discrimination ordinance compels Hitching Post owners Don and Lynn Knapp to perform same-sex marriages. The lawsuit says that violates the couple's constitutional rights to religious freedom.

But Gridley said the ordinance exempts not-for-profit religious entities, but not for-profit businesses.

The Hitching Post is registered as a for-profit limited liability company with the Idaho Secretary of State. However, on Oct. 6, the Kanpps filed with the state as a religious organization. Gridley, in his letter to Alliance Defending Freedom, said that if the Kanpps are "truly operating a not-for-profit religious corporation" they would be exempted from the city ordinance.

Gridley wrote that the city doesn't intend to prosecute legitimate nonprofit religious corporations.

"Their lawsuit was something of a surprise because we have had cordial conversations with them in the past and they have never disclosed that they have recently become a religious corporation," Gridley wrote.

Gay marriage became legal in Idaho on Oct. 15.