A handful of Amazon workers in Shakopee, far fewer than the 100-plus organizers had expected, walked off the job in the middle of their shifts to protest work conditions at the sprawling fulfillment center on Monday.

The strike was timed to coincide with the first day of the two-day Prime Day sale, which has become one of Amazon’s biggest shopping events of the year. The protest has drawn national attention in recent days since this was one of the first time workers in the U.S. have challenged Amazon — which disputes their complaints — through a work stoppage.

Mohamed Hassan, a packer in the fulfillment center, walked out into the blazing sun and a crowd of supporters waiting on the sidewalk Monday afternoon a few hours before his shift was over.

“We were expecting a lot of workers to come out today,” he said at a rally, speaking through an interpreter. “There were managers, supervisors and police that are standing at the gates and front doors, so they’re scared because of that. That’s the reason they couldn’t come out, and I’m sad for that.”

He said later that the workload is too demanding and that he has injured his wrists from moving heavy boxes.

The protest is one of the latest actions organized by the Awood Center, a Minneapolis-based group that advocates for the workers. One of the workers’ principal complaints is that they are asked to work too fast, sometimes getting hurt, in order to make Amazon’s industry-leading quick deliveries possible. The workers are also asking for the right to organize as well as better advancement opportunities and quicker transitions from temporary to full-time status.

As they waited for workers to walk out, a group of supporters carrying signs marched and chanted: “Together, we can make history in every warehouse, in every city.” Some wore shirts that said “We’re humans, not robots.”

Among those carrying a sign was Zach Ali, 22, of Shakopee. He has been working at Amazon for a year as a restocker. Monday was his day off, so he didn’t have to walk off his shift, but he wanted to show up anyway to voice his concerns.

“It’s very tough,” he said of working at Amazon. “To have only two breaks of 30 minutes in a 10-hour shift is absurd. If you ask me, it’s modern-day slavery.”

Brenda Alfred, an Amazon spokeswoman, said about 20 workers clocked out in the middle of their shifts during the day on Monday, but it was hard to know how many of them were leaving to strike or for other reasons. Some workers also were expected to walk out during the evening shift.

She said that police and other personnel were standing near the entrance to ensure the safety of workers, given the protest, and not to intimidate workers.

Amazon’s 885,000-square-foot Shakopee fulfillment center is one of about 110 Amazon has around the country. It employs about 1,500 workers.

“Many people know that Prime Day is an exciting day and it draws a lot of attention,” Alfred said. “There are certain outside organizations that are taking the opportunity today to try to elevate the awareness of their cause to try to potentially gain membership and to get people to pay union dues.”

She added that Amazon already provides a lot of things the protesters are asking for.

About 90% of Amazon workers in Shakopee are full-time, and more than 100 temporary workers have been converted to full-time positions so far this year, with 30 more offered such roles in the past week, Alfred said.

Second shift gets high-fives

She added that worker performance is measured and evaluated over a “long period of time, as we know that a variety of things could impact the ability to meet expectations in any given day or hour.” Amazon’s policy is that more than 75% of workers should exceed rate expectations before changes are considered, and those who are not performing at that level are given dedicated coaching to help them improve, she said.

Inside the fulfillment center, a row of managers and supervisors welcomed workers arriving for the second shift of Prime Day with high-fives along an orange carpet while pop tunes blared over the speakers.

But outside, and around the nation, many eyes were focused on the protest, which was mostly made up of supporters.

Among those expressing support for the Amazon workers’ strike on Monday was Democratic presidential candidate Elizabeth Warren, who tweeted: “Their fight for safe and reliable jobs is another reminder that we must come together to hold big corporations accountable.”

Three tech workers from Amazon’s Seattle headquarters flew down to Minnesota to show their solidarity with workers. They are part of an employee group, Amazon Employees for Climate Justice, that has been pushing the company to reduce its reliance on fossil fuels.

Capt. Michael Russo of the Teamsters Local 1224, who represents pilots who make deliveries for Amazon Air, also spoke at the rally, along with elected officials. Those pilots, who work for contractors Atlas Air, Southern Air and ABX Air, have also been raising their voices about being overworked and underpaid and have been asking Amazon to intervene as they try to negotiate new contracts.

In Germany, Amazon workers, who have been agitating for better pay and working conditions, also went on strike Monday.