A federal mediator will try to break a salary-negotiation impasse between the Salt Lake City Police Association and the city.

Mayor Palmer DePaulis said it is the first time a mediator has been needed to settle a labor dispute with the city, but he doesn't see that as a bad sign."This is just a tool," he said. The police union called for the negotiator earlier this week.

The mediator will begin meeting with both sides Friday. The police union is asking for a 4 percent cost-of-living raise. The city is proposing only a 1 percent raise with an average merit raise of 2.75 percent and an additional 1 percent bonus for each employee.