Striking city workers are joining picket lines outside Philadelphia City Hall, public libraries and other worksites as nearly 10,000 unionized employees walked off the job in search of better pay and benefits.

Greg Boulware, president of District Council 33 of the American Federation of State, County and Municipal Employees, called for an immediate and indefinite work stoppage of the more than 9,000 municipal employees he represents after contract negotiations with Mayor Cherelle L. Parker ’s administration fell apart late Monday night.

Nearly 10,000 city workers in Philadelphia who collect trash, answer 911 calls, maintain city pools and perform other jobs are on strike.