The union of 30,000 members serving a district of 600,000 students has said it will strike as early as Thursday.
The Los Angeles teachers' union and school district officials were trying to hammer out a last-minute deal on Monday to avoid a massive strike planned for Thursday.
In a statement Sunday, United Teachers Los Angeles said it hoped the Los Angeles Unified School District, which with 600,000 students is the nation's third-largest, would offer "a meaningful proposal" after months of stalled contract negotiations.
A district spokeswoman confirmed the negotiations but declined to provide additional details.
The union, which represents more than 30,000 teachers and other school staff, has pushed the district to spend "a substantial" portion of a $1.9 billion reserve to reduce class size and hire more staff, among other demands.
Last week, the district accused the union of refusing to resume contract negotiations after the release of a fact-finding report last month — and an apparent offer that included a 6 percent pay raise and $30 million in funding, NBC Los Angeles reported.
But the union countered that the details of that offer remain "unclear," and that salary increases could require future health care cuts, the station reported.
The union said a possible injunction sought by the district could delay Thursday's walkout, but that such a victory would be "fleeting" because "it will only delay UTLA's right to strike by a few days."