ABC News - March 31, 2015, Candice Choi - Fast-food labor organizers say they're expanding the scope of their campaign for $15 an hour and unionization, this time with a day of actions including other low-wage workers and demonstrations on college campuses.

Kendall Fells, organizing director for Fight for $15, said Tuesday the protests will take place April 15 and are planned to include actions on about 170 college campuses, as well as cities around the country and abroad.

At an event announcing the actions in front of a McDonald's in New York City's Times Square, organizers said home health care aides, airport workers, adjunct professors, child care workers and Wal-Mart workers will be among those turning out in April.

Terrence Wise, a Burger King worker from Kansas City, Missouri, and a national leader for the Fight for $15 push, said more than 2,000 groups including Jobs With Justice and the Center for Popular Democracy will show their support as well.

"This will be the biggest mobilization America has seen in decades," Wise said at the rally as pedestrians walked past on the busy street.

The plans are a continuation of a campaign that began in late 2012. The push is being spearheaded by the Service Employees International Union and has included demonstrations nationwide to build public support for raising pay for fast-food and other low-wage workers, although turnout has varied from city to city. Last May, the campaign reached the doorsteps of McDonald's headquarters in Oak Brook, Illinois, where protesters were arrested after declining to leave the property ahead of the company's annual meeting.

Fells, an SEIU employee, said April 15 was picked for the next day of actions because workers are fighting "for 15."

"It's a little play on words," he said.

Fells noted that while the push began as a fast-food worker movement, it has morphed into a broader push for low-wage workers and is now shifting into a social justice movement with the involvement of "Black Lives Matter" activists joining in in the April protests. Still, he said McDonald's Corp. remained a primary target.

"McDonald's needs to come to the table because they could settle this issue," he said.

In a statement, McDonald's said it respects people's right to peacefully protest, but added that the demonstrations over the past two years have been "organized rallies designed to garner media attention" and that "very few" McDonald's workers have participated.

In addition to the ongoing demonstrations, organizers have been working on multiple fronts to make the legal case that McDonald's Corp. should be held accountable for working conditions at its franchised restaurants. That finding is seen as critical in being able to negotiate with one entity on behalf of workers across the chain, rather than dealing with the thousands of franchisees who operate the majority of McDonald's more than 14,000 U.S. restaurants.

McDonald's and other fast-food chains have maintained that they're not responsible for hiring and employment decisions at franchised locations.

One closely watched case addressing the matter began this week, when the National Labor Relations Board began hearings on complaints over alleged labor violations at McDonald's restaurants. The board's general counsel had said last year that McDonald's could be named as a joint employer along with franchisees in the complaints.

The hearing is scheduled to resume May 26 and is set to be a lengthy legal battle. Whichever side loses is expected to appeal, with the possibility of the case eventually heading to the Supreme Court.

In a statement, McDonald's has said the board's decision to name McDonald's as a joint employer "improperly strikes at the heart of the franchise system."

"The SEIU put a target on McDonald's back more than two years ago; the Board has now joined in taking aim, and has done so by managing the McDonald's case in an unprecedented manner," the statement said.