Los Angeles, March 22 : Tens of thousands of school workers kicked off a three-day strike, shutting down the Los Angeles Unified School District, the second-largest school district in the US. The Service Employees International Union Local 99, a union that represents 30,000 school workers in the Los Angeles Unified School District (LAUSD), including cafeteria workers, special education assistants, custodians, bus drivers and others providing essential student services, said the it is striking over "unfair labour practices". "It's time for #LAUSD to hear the voices of thousands of workers who are speaking out to improve their livelihoods and the student services they provide," the union tweeted. The union hosted a rally at LAUSD Headquarters on Tuesday morning, Xinhua news agency reported. Hundreds of school employees, many among the lowest-paid, joined the picket line before 5 a.m. local time and other strikers have taken to the picket line at many school sites throughout the sprawling district, reported the Los Angeles Times. The newspaper said the strike will disrupt learning, vital meal services and the daily lives of nearly 4,20,000 children and their families. The union is demanding a 30 per cent salary increase, plus two US dollars more per hour for the lowest-paid workers, according to the report. The Los Angeles Unified School District tweeted on Monday that school officials "continue to work around the clock, doing everything we can to minimise disruption to student learning". Los Angeles Mayor Karen Bass said in a statement that she has authorised resources to be provided to support LAUSD families in the event schools are closed. "In the event Los Angeles Unified Schools are closed, we are ready to provide safe places and meals so students are cared for and parents can keep working," she noted, adding that "schools are so much more than centres of education -- they are a safety net for hundreds of thousands of Los Angeles families". /IANS