Some Amazon employees around the world are going on strike on Amazon Prime Day, the most highly anticipated discount shopping day of the year, to protest working conditions and demand better pay, Market Watch reports.

The strike has been extended from one day to two—July 15 through July 16. At least 2,000 workers in Germany, Spain, and Poland, as well as more than 100 workers in Minnesota, are striking, organizing around the slogan, “No more discount on our incomes.”

Amazon Workers Walk Out To Protest Working Conditions, Unequal Pay

More from Market Watch:

The strike comes as Amazon, which employees more than 600,000 people globally, extended the Prime Day sale for the first time ever to two days from July 15 to July 16 and promised one-day delivery on many items. Employee advocates say that will put more physical pressure on workers to keep up with demand. … One U.S. Amazon warehouse employee in Minnesota said she’s expected to physically handle and drop off 600 items per hour while staying on her feet continuously.

“We’re humans, not robots,” William Stolz, an Amazon warehouse worker in Shakopee, Minnesota, told CNN Business. “They’re treating us like machines.”

According to CNN Business, Amazon raised starting wages to $15 an hour for all US employees last year, but workers say they are still not treated with respect; further, they say that they are subjected to dangerous conditions, unfair scheduling, and “impossible demands,” with conditions not being equitable across factories. Demonstrations are planned in New York, San Francisco, Seattle and Washington, DC, in solidarity. Sen. Bernie Sanders and Sen. Elizabeth Warren, have both voiced support for the Amazon Prime Day Strike.