Building owners and union leaders will continue talks through the weekend to settle a janitors’ strike, Mayor Antonio Villaraigosa announced Thursday.

Hundreds of janitors at 20 buildings on L.A.’s Westside walked off their jobs Wednesday night after contract talks with building owners broke off earlier in the day.

Villaraigosa had convened a meeting of building owners and the Service employees International Union Local 1877 on Thursday that he said resulted in the union accepting a “cooling off” period while negotiations resume, averting a strike.

The walkout came after janitors voted to authorize a strike around noon on Wednesday, according to Local 1877 President Mike Garcia.

The contract between SEIU Local 1877 and building owners expired on April 30, but was extended last week until Wednesday to allow for more negotiations.

Garcia said the talks broke down over the issue of a two-tier pay and benefits system, which provide higher pay and benefits to janitors at buildings in Downtown Los Angeles and Century City than buildings elsewhere on the Westside.