Fells declined to say what exactly is in store for the protests in around 150 U.S. cities. But workers involved in the movement recently cited sit-ins as an example of strategies they could use to intensify their push for higher pay and unionization. Past protests have targeted a couple of restaurants in each city.

The “Fight for $15” campaign is being backed by the Service Employees International Union and has gained national attention at a time when growing income disparities have become a hot political issue.

President Obama and others have said raising wages for those at the bottom of the economic ladder could help strengthen the middle class.