The vast majority of fast-food workers in the U.S. say they've been the victims of wage theft, according to a newly released survey.

Out of 1,088 respondents nationwide, 89% said they have been forced to do off-the-books work, been denied breaks, been refused overtime pay or been placed in similarly unsavory circumstances.

The same holds for 84% of McDonald's workers, 92% of Burger King employees and 82% of Wendy's rank and file, according to the survey, which was conducted by Hart Research for the Low Pay Is Not OK campaign.

The campaign is part of an effort to raise minimum wage for fast-food workers to $15 an hour and to push companies to let their workers unionize without retaliation.

In the Los Angeles metropolitan area, the only California region surveyed, 81% of fast-food employees said they have experienced wage theft.

The survey was conducted online from Feb. 15 to March 19. Respondents were recruited with ads placed on Facebook using an algorithm designed to target fast-food workers.

Participants hailed from Los Angeles, New York, Chicago, Dallas, Houston, Philadelphia, Miami, Atlanta, Boston and Washington, D.C. The group represents a variety of ages, experience levels, hours worked and wages earned.

One-third were white, one-quarter were black and 30% were Latino. More than one-quarter said they work or used to work for McDonald's; the rest were associated with chains such as Burger King, Subway and Wendy's.

Nationwide, 60% of respondents said they were forced to perform tasks while off the clock, slightly more than the 59% of Angeleno workers who made the same assertion.

Fast-food companies across the country haven't paid 46% of workers for all the time they put in and the duties they completed, according to the survey.

More than 4 in 10 workers said they weren't given breaks during long shifts, slightly more than the number who said they had the cost of their uniform deducted from their paycheck.

Other alleged misdeeds: employers paying workers late, asking employees to wait before cashing their paychecks or forcing cashiers to pay up if the cash register's contents don't match records.

The majority of workers included in the survey said they had experienced three or more forms of wage theft. Eight in 10 said they consider their working conditions to be just fair or poor -- the same percentage as in Los Angeles, where nearly one-third of respondents said they work two or more jobs.

Most employees think their companies could afford to improve the situation, according to the survey.