Long-festering employee discontent at Amazon.com, the world’s largest e-commerce marketplace, once again surfaced with fulfillment center workers in Shakopee, Minnesota walking out Monday afternoon in the midst of the two-day Amazon Prime Day that began on the same day.

Minnesota employees said they’ll go on strike for a six-hour period that overlaps with the morning and evening shifts. They’re protesting dangerous working conditions, wage practices, unfair scheduling and impossible demands being made on them on a daily basis by management.

Media reports said there were about 75 workers outside the fulfillment center (called MSP1) at 5:00 p.m. ET Monday. The striking employees shouted “We work, we sweat, Amazon workers need a rest!” and “Amazon, hear our voice!”

The Minnesota strike is the first major strike of Amazon workers in the U.S. during Amazon’s annual Prime Day sales extravaganza. Analysts said the strike might also be a warning sign Amazon’s move to increase to increase its minimum wage to $15 per hour is insufficient to satisfy workers’ needs.

The exhausting nature of fulfillment center jobs seems to be a huge issue among employees.

“Amazon has the means to do so much more for all of its employees, and we would like to see less physically and mentally draining jobs,” said William Stolz, who has worked in an Amazon warehouse for over two years, according to CNBC’s “Closing Bell.”

“We would like to see workers have better job security, better treatment for those that are injured, bringing back some of the benefits and bonuses that we used to have.”

The American Federation of Labor and Congress of Industrial Organizations (AFL-CIO), the largest federation of unions in the United States, threw its wholehearted support behind the striking workers and also released a video Monday expressing solidarity with the strikers.

“They’re working under insane deadlines, often in unsafe conditions,” said AFL-CIO Secretary-Treasurer Liz Schuler in the video. “We’re standing strong in solidarity with the workers in Shakopee and beyond, but we hope you will too. When you stand up together collectively, that is how we change corporate behavior.”

Presidential hopefuls of the Democratic Party, especially those known to champion workers’ rights, also showed their support.

On Monday, Sen. Elizabeth Warren (D-MA) tweeted: “I fully support Amazon workers' Prime Day strike. Their fight for safe and reliable jobs is another reminder that we must come together to hold big corporations accountable.”

Sen. Bernie Sanders (I-VT) said Amazon workers deserve higher wages, safe working conditions, fair scheduling, and reasonable production demands.

There’s a cultural aspect to the Minnesota strike, as well. Most of the workers at MSP1 are East African Muslims and they’ve previously protested Amazon’s disregard for their religious practices.

For these East Africans (mostly Somalis), the strike is part of their demands Amazon “provide safe and reliable jobs, increase respect and opportunities for advancement for the predominantly East African workforce, protect the right to organize and advocate for better working conditions, and to demand concrete action from Amazon to address critical issues like climate change,” said the organizers.

Amazon Minnesota Demonstrators shout slogans and hold placards during a protest at the Amazon fulfillment center in Shakopee, Minnesota, on December 14, 2018. A group of Amazon workers in Minnesota who are Somali refugees resettled in the Midwestern US state demanded better working conditions during a protest outside one of the retailer's warehouses. Photo: KEREM YUCEL/AFP/Getty Images

The Minnesota strike follows a similar one in Germany where more than 2,000 walked out of their jobs at seven company locations across Germany. The striking Germans demand Amazon provide better pay and benefits and demand the company comply with a collective bargaining agreement. The strikers have adopted the slogan, "No more discounts on our incomes."

"While Amazon fuels bargain hunting on Prime Day with hefty discounts, employees are being deprived of a living wage," said Orhan Arkan, a retail specialist in the Verdi workers union.

In reply to the strike, Amazon claims it’s already granted the strikers’ demands.

“These groups are conjuring misinformation to work in their favor, when in fact we already offer the things they purport to be their cause -- industry leading pay of $15 per hour, benefits, and a safe workplace for our employees,” said Amazon.

“If these groups -- unions and the politicians they rally to their cause -- really want to help the American worker, we encourage them to focus their energy on passing legislation for an increase in the federal minimum wage, because $7.25 is too low.”