MINNEAPOLIS (AP) — The campaign group trying to defeat the gay marriage constitutional amendment is getting ready to air its first TV commercial.

Minnesotans United for All Families announced via Twitter Friday that its first ad would air in the next week. The group was not releasing further details Friday, but a Federal Communications Commission filing showed a $255,000 buy for a 30-second spot to air on six Twin Cities TV stations from Sept. 17-23.

The amendment on the November ballot asks voters if a gay marriage ban already in state law should be added to the constitution.

Another opposition group, Freedom to Marry, already aired a TV ad against the amendment. Minnesota for Marriage, which supports the amendment, is also reserving airtime for ads to start around Oct. 1.

(© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)