The suit was filed on behalf of all women employed by Google in California over the last four years.

SAN FRANCISCO — Google is being sued for gender pay discrimination, turning up the heat on the Internet giant already facing allegations it shortchanges women.

Three female former Google employees are seeking class-action status for the complaint filed Thursday in San Francisco Superior Court.

The lawsuit comes as the Labor Department investigates systemic pay discrimination at Google. Google says its own analysis found no pay gap.

In a statement to USA TODAY, Google said it would review the lawsuit but disagreed with “the central allegations.”

The lawsuit is being brought by three women — Kelly Ellis, Holly Pease and Kelli Wisuri — who say they quit Google after being placed at lower job levels, resulting in lower pay and denying them promotions and moves to other teams that would advance their careers.

The plaintiffs allege women at all levels of Google are paid less than men and that women are assigned to lower job tiers with less opportunity for upward mobility. 

“Women should have the same opportunities as men, and receive equal pay for substantially similar work,” Wisuri said in a statement. 

Attorney James Finberg of Altshuler Berzon who, with attorney Kelly M. Dermody of Lieff Cabraser Heimann & Bernstein, is representing the women, says Google long has been aware of the problem and has done nothing to fix it.

The Labor Department’s investigation prompted Finberg to ask female Google employees to come forward if they had experienced pay discrimination. He and the other lawyers heard from 90 current and former employees.

“That’s a strong outpouring of dissatisfaction,” Finberg said. “The stories of the women were consistent with what the Labor Department found, that women are paid less in every category.”

More: Google must turn over records on women’s pay

More: Google employee spreadsheet alleges pay gap for women

More: Google’s new diversity chief tasked with moving the needle

More: Women coders respond to ex-Googler Damore: Nope.

Google spokeswoman Gina Scigliano said job levels and promotions are determined “through rigorous hiring and promotion…