Public hospitals diverted ambulances. Beach crews cleared wildfire debris without heavy equipment. Libraries closed. Thousands of nurses stayed home.

A two-day strike in Los Angeles County kept some 55,000 unionized public employees off the job on Tuesday, as workers gathered at an enormous rally that clogged streets in downtown Los Angeles.

The walkout by the public employees union, SEIU Local 721, came as contract negotiations between the nation’s largest county and the county’s largest union snagged in the face of intense budget pressures. Both the city and county governments in Los Angeles have struggled in recent months to deal with an onslaught of financial problems, including huge legal liabilities, threats to federal funding under the Trump administration and the cost of the January wildfires.

Last week, city officials — who stretched last year to grant their unions generous pay raises — traveled to Sacramento to ask state legislators for help with a projected shortfall of nearly $1 billion. Mayor Karen Bass of Los Angeles warned that without a state rescue, the city might have to lay off some 1,650 workers.

Los Angeles County, a much larger entity that acts as the social safety net for millions of Southern Californians, announced this month that its financial stressors were also mounting.

Among them: projected wildfire-related costs approaching $2 billion; hundreds of millions of dollars in health grants that have been jeopardized by the Trump administration; and a $4 billion settlement for thousands of sex abuse claims brought by former wards of the county’s foster care and juvenile detention systems, dating back decades.