Gov. Jerry Brown is targeting a new part of the budget to close a widening deficit by seeking to reduce state worker costs in his revised spending plan, according to sources with knowledge of his plans.

Brown, who has been in discussions with labor unions, is expected to release an updated budget proposal on Monday. The sources were not authorized to speak publicly before the governor's announcement.

The possibility of cuts to state employees is a symptom of lagging tax revenue. California has collected $3.5 billion less taxes than expected in the current fiscal year, according to the controller, and the budget gap will be larger than the $9.2 billion estimated in January.

Brown spared state employees when he released his preliminary budget proposal earlier this year, but sources said he will now ask them to shoulder cuts as the red ink piles up.