The Los Angeles Unified School District (LAUSD) and the United Teachers Los Angeles (UTLA) negotiations appeared headed to a mediator.

Last week, the teachers union declared an impasse in protracted contract negotiations with the nation’s second-largest school system, and LAUSD officials said they agreed there was an impasse.

LAUSD officials said their offer of a 5 percent pay raise retroactive to July 1, 2014, along with proposals on evaluations, class sizes, and parent engagement, are public and ready to be implemented.

“I’ve been disappointed and frustrated by the lack of progress toward an agreement,” LAUSD Superintendent Ramon C. Cortines said. “It’s my hope that the appointment of a mediator will lead to an expeditious settlement that ultimately supports our students and the district at large.”

Proposals from the district and the union remain more than $800 million apart.

UTLA is seeking an 8.5 percent one-year pay increase. Teachers have not had a pay raise or cost of living increase in eight years, although teachers have continued to receive pay boosts based on education credits and experience.

UTLA is also calling for smaller class sizes and an increase in school staffing.

“UTLA will not accept a piecemeal agreement that addresses only one or two issues, which fails to improve student learning conditions and educator working conditions,” the union said in a statement.

LAUSD officials said they have repeatedly requested for the union to accurately identify additional ongoing sources of funding.

“The district invites the opportunity for independent review of our books to demonstrate that given budget realities, our 5 percent salary increase is fair and generous,” LAUSD said in a statement. “As before, district negotiators would like to conclude an agreement at the table. Perhaps with the active participation of a mediator, UTLA will have a sense of urgency, which considers our fiscal reality.”