The board of the Los Angeles Unified School District has voted to send notices of possible layoffs to up to 5,200 teachers and other workers because of a huge budget gap.

The Board of Education was unanimous Tuesday in deciding to take the action as the nation's second-largest school district deals with a $640 million shortfall.

At the same time, the board has urged union leaders to enter negotiations that could make some layoffs unnecessary.

The vote does not constitute a decision to actually begin layoffs. The district sometimes rescinds such notices if more money becomes available.