A strike by World Cup stadium security guards in South Africa has forced World Cup organizers to turn to local police to guarantee safety at many venues.

Before the June 15 match between Brazil and North Korea at Ellis Park in Johannesburg, several hundred protesting workers dressed in black, sang, chanted and whistled as people poured into the stadium, according to The Los Angeles Times.

The strike stems from a dispute over pay between temporary, short-term security workers and their employer, Stallion Security Consortium, the private security company World Cup organizers hired to secure stadiums in Cape Town, Durban, Port Elizabeth and Johannesburg.

The issue initially arose on June 13 at Moses Mabhida Stadium after the Germany vs. Australia match. According to The Wall Street Journal, riot police were called in to disperse an angry crowd of workers.

Many South Africans believe that the wealth pouring into the country from the World Cup isn’t trickling down to everyone. In the case of the strikers, they say they’re being offered from 126 rand to 190 rand, equal to $16.50 to $25, for 12- to 15-hour shifts. They’re asking for at least 450 ran per day, or about $59.

Stallion’s attempt to get the guards to stop protesting and return to work has been unsuccessful All the guards involved in the strike have been fired.

“This has all been very sad. Unfortunately, very few of the people affected have had permanent jobs and are all temporary, which makes it difficult to speak for them,” Robert Mashego, deputy president of the South African Transport and Allied Workers’ Union, which has represented workers in the dispute, told the Christian Science Monitor. “When the FIFA tournament is over on July 11, they won’t have a job anyway so it is difficult to settle a dispute like this.”

Protests are also planned to occur at the rest of Mexico’s games at the World Cup as South African union workers are displeased with the Mexican government’s treatment of Napoleon Gomez Urrutia, a miner’s union leader in that country.