BILLINGS (AP) — The Billings city council is drafting an ordinance that would ban sexual activity at massage parlors.

Council members discussed the issue this week, saying an ordinance would protect legitimate businesses while addressing prostitution and human trafficking.

FBI Agent Brandon Walter told the council during Monday’s work session that there were 20,000 ads posted online between October 2016 and October 2017 offering sex for sale in Billings, with about half of them posted by Billings massage parlors. By comparison, Bozeman and Missoula had about 5,000 ads during the same time.

Walter suggested the council pass an ordinance and step up enforcement.