The mayor of Bloomington plans to conduct a wedding ceremony for more than a dozen gay and lesbian couples to protest a proposed constitutional amendment banning gay marriage in Indiana.

The ceremony, Thursday, coincides with a local lesbian, gay, bisexual and transgender festival.

Local clergy and city officials are expected to attend.

Legislators approved a constitutional ban in 2011, but it must be approved again and pass a referendum before taking effect. Two ban bills were introduced in the Indiana House last week, but their future is unclear.

Critics say a constitutional amendment is unnecessary because same-sex marriage is already illegal under current law.