Workers walked off their jobs at fast-food restaurants across the country Thursday as part of a national protest against low wages, a day after President Barack Obama renewed his call for a minimum wage hike.

The action is part of a growing movement against what workers say are substandard working conditions and wages too low for employees to make ends meet. Thousands of labor activists and workers, who were scheduled to start their shifts early Thursday morning, did not show at their jobs and chose to protest instead.

Workers and their supporters are expected to strike at the nation's major national fast-food restaurants, organizers said, including McDonald’s, Burger King, Wendy’s and KFC. Protesters in cities such as Charleston, S.C., Providence, R.I., and Pittsburgh will join the action for the first time, along with clergy, elected officials and community supporters.

About 150 fast food workers, community organizers and union members staged a rally outside of a Wendy's burger joint in Brooklyn, New York City, at noon on Thursday.

Carrying signs and placards calling for a $15 dollar wage, up from $7.25 right now, they marched in front of the restaurant, which had "voluntarily closed," a police officer present said. Security guards stood inside the doors watching rally chant slogans.

"Getting paid $7.25 for work, it makes me feel like a slave really. My back hurts and I'm in pain. I call out and I don't get paid for the day. If I hurt myself I can't leave or I get written up, said Adam Haynie, 21, who has been working at the Wendy's for six months.

Haynie also described having his hours cut at his manager's whim. Sometimes he will only get five hours of work per shift, he said.

Keirra Washington, 19, from East New York, Brooklyn, who has been working at the Wendy's for a month, said its manager hires more people than necessary, and sends home workers when they're deemed unnecessary for the shift.

"Twenty people just wasted car fare," Washington said.

Cynthia Green, 51, who has been working at a KFC in Brooklyn for 13 years and walks with a cane, said a $15 minimum wage would help her make ends meet. "That would help me be able to pay my rent without help from the government." She said she tries to work through her disability which requires her to use a cane. "I have my good days and bad days. I do my job."

Eric Channax, 41, who was watching the demonstrators in New York from nearby, said he doesn't agree with the fast-food workers' demand to get paid more.

"I think it's a bunch of Marxist philosophy. I think they're wrong to demand that. The government shouldn't dictate the private sector," he said. "I'm an electrician. I rely on the free market system. We get paid on our skill level. Not because the government says so, but because we're capable."

In Detroit, dozens of McDonald's employees and others marched in front of a restaurant during the predawn rally Thursday, carrying signs and shouting familiar phrases: "Raise the minimum wage" and "Hey, hey, ho, ho, $7.40 has got to go," the Associated Press reported.

McDonald's maintenance worker Julius Waters was among those protesting. The 29-year-old from Detroit told the AP his $7.40-an-hour wage pays for his transportation to and from work but not much else.

Waters said $15 an hour would help him and his 6-year-old son improve their standard of living.

In a speech Wednesday, the president suggested that addressing income inequality would be a focus of his remaining three years in office. Since 2009, the income of the top 1 percent has increased by nearly a third, while the salaries of the other 99 percent rose only 0.4 percent. Obama suggested the minimum wage of $7.25 should be hiked to $10.10, and called inequality the "defining challenge of our time."

"The idea that a child may never be able to escape that poverty," said Obama, "because she lacks a decent education or health care, or a community that views her future as their own, that should offend all of us. And it should compel us to action. We are a better country than this."

Working full time at minimum wage means that employees make just $15,000 a year. That is below the federal poverty level for a single parent with one child and could result in their having to hold back on purchasing basics.

Thursday's strike is similar to recent actions across the country focusing on income inequality. On Black Friday, some workers at Walmart walked off their jobs and demanded higher wages of at least $25,000 a year. In a first success, the wages of 6,000 airport and hotel workers at the Seattle-Tacoma International Airport increased from $7.25 to $15.

The fast-food strike movement gained traction last year in New York City, when around 200 workers walked off their jobs. In August, workers from about 60 cities participated in strikes and disrupted service. Now the organizers hope to rally workers in 100 cities. They also want to be able to unionize without any fear for retaliation.

The restaurant industry has said that sharply higher wages would lead to steeper prices for customers and fewer opportunities for job seekers. It has also said that most of the people who are participating in the strikes aren't actually workers but PR groups and unions who support this cause.

Philip Dine, a U.S. labor expert and commentator, told Al Jazeera he doesn't believe that industry predictions over the impact on prices and hires are accurate.

"I don't think a few dollars more of a highly profitable sector is going to lead to restaurants laying off workers," he said. "In this country we have working people who just cannot afford to pay for the products they're making."