PORTLAND, Ore. (AP) — The Portland Police Association said Monday it is taking its ongoing contract negotiations with the city to mediation.

The move means the partially public negotiations will no longer have a public element, as the two sides negotiate the thorniest remaining unresolved issues, Oregon Public Broadcasting reported.

“After 11 bargaining sessions … we have made progress on a successor collective bargaining agreement—but not enough progress,” the union announcement says.

Under collective bargaining laws, the city of Portland or the police union can seek mediation after 150 days of contract negotiations.

In a response news release, Chief Deputy City Attorney Heidi Brown said the city respects the state’s labor laws, but noted mediation was not the city’s preference.

Over the past five months, lawyers representing the city and the union have reached tentative agreement on 30 articles of the current 68-article contract. Many of the agreed-upon changes are minor language updates and tweaking how officers are paid when working in a position typically reserved for a higher ranking officer.

The two sides also agreed to remove gender pronouns, ensure that the term spouse includes domestic partners, and added post-traumatic stress disorder to work-related injuries covered by the the city.

The private mediation process lasts at least 15 days. If agreement isn’t reached, an arbitrator will review each sides’ “last best offer” and pick one. That decision will be legally binding.