A week after employees in three states filed lawsuits alleging wage theft by McDonald's Corp., fast-food workers demonstrated for higher pay Tuesday outside franchise restaurants in Pennsylvania.

Outside a McDonald's a mile and a half due north of Philadelphia's City Hall, Robyn Richardson said she's worked in other fast-food restaurants for years and her wages have always been low.

"I only make $8 an hour," she said. "And I'm a single mother, and I'm trying to take care of my son. And $8 isn't doing it."

The class-action filings in Michigan, New York and California claim McDonald's has denied pay and overtime to workers.

Richardson was one of several dozen demonstrators in Philadelphia. The Service Employees International Union said similar demonstrations by fast-food workers will take place in more than 100 cities this week, including Wilmington, Delaware.

State Sen. Daylin Leach, D-Montgomery, spoke with protesters about his plan for increasing Pennsylvania's minimum wage to $12 and end the tipped minimum wage. State law allows for a tip credit that lets employers use tips against all but $2.83 of the current $7.25 minimum wage.

"People shouldn't be living in poverty if they're working back-breaking work for 40 hours a week," said Leach, who is co-sponsoring the measure with state Sen. Mike Stack.

A representative of McDonald's did not respond to a request for comment.