Greeley-Evans School District 6 and a teachers union are headed for federal mediation over stalled contract negotiations.

The Greeley Tribune reports district officials said in an email Tuesday that the two sides were at an impasse.

A similar deadlock was reached last year. Mediation was unsuccessful and the district board ultimately imposed contract terms.

Greeley Education Association president Pat Otto said in a statement that she was disappointed in the district's decision to head for mediation.

District 6 spokeswoman Theresa Myers says it seemed unlikely the two sides would reach a compromise.

A major point of contention is the district's suggested 2 percent bump in base pay that teachers say should be at 3.75 percent.