The Burgerville Workers Union announced Wednesday that union workers walked off the job at four locations to begin a strike.

The unionized workers are striking at the Convention Center, 92nd and Powell, Hawthorne and Montavilla locations. Workers at a fifth unionized location in Gladstone were still at work as of Wednesday.

The workers are striking for wage increases after union negotiations fell through with the Vancouver-based fast food chain last week.

Natalie Bennon, a spokesperson for Burgerville, said the affected stores are remaining open during the strikes.

“Not all workers walked off, so currently all locations are open and will remain open as long as we can ensure safety and well-being of employees and customers,” Bennon said.

The union said workers will remain on strike until they’ve “sufficiently demonstrated their strength to the company.”

“We are proud of this strike and are in awe of the courage displayed by all our coworkers today,” a statement from the workers union reads. “But we are disappointed that the struggle at Burgerville has come to this. In the almost year and a half of contract negotiations, we have made a great deal of progress: from tips and holiday pay to protections for undocumented workers.

“When it comes to the biggest issue of all, however – an end to poverty wages at Burgerville – corporate refuses to budge.”

The union said striking workers are inspired by a long time Burgerville worker in Vancouver who it said was suspended Sunday for standing up to racism from his manager.

“As of today, Anthony’s job remains in jeopardy,” the statement said. “Anthony’s story reminds us of the petty and retaliatory behavior we have seen from this so-called progressive company over and over.”

In a statement from Burgerville, the company said it does not treat union members or employees of color differently than other employees at its restaurants.

“Burgerville has clear employment policies that are fairly and consistently enforced across the board regarding shift meals, attendance, safety and other matters,” the company said.

The Burgerville Workers Union said it will continue to host public action events this week to support striking employees, including a picketing event at the restaurant’s Convention Center location at 5 p.m. Wednesday.