(CNN) - Workers at Amazon facilities in Germany have gone on strike in a protest over pay and working conditions as Prime Day gets underway.
The strikes, held under the slogan "No more discount on our incomes", started Sunday night at Amazon sites in Werne, Rheinberg, Leipzig, Graben, Koblenz and Bad Hersfeld, German union Verdi said in a statement.
The protests were expected to continue at least through Monday. They are being held to coincide with Amazon Prime Day — a discount event held on Monday and Tuesday for Amazon Prime customers.
"While Amazon throws huge discounts to its customers on Prime Day, employees lack a living wage," said Verdi retail specialist Orhan Akman.
The union also called for collective bargaining agreements to be made binding across Germany's retail sector.
"The company must finally recognise collective agreements for the retail and postal sectors; wages and salaries cannot be determined in the style of lord of the manor," Akman said.
A spokesman for the union told CNN Business that more than 2,000 people had participated in the strike.
Amazon has been embroiled in a dispute with German trade unions over pay and working conditions for years. The company's workers in Germany have staged frequent strikes and protests since 2014, according to Verdi.
The online retail giant said the strike was having no effect on operations.
"While we don't provide exact numbers, we are seeing very limited participation across Germany with zero operational impact and therefore no impact on customer deliveries," an Amazon spokesperson told CNN Business.
Nearly 18,000 people work for the company in Germany. On Sunday, Amazon announced plans to create more than 2,800 additional permanent jobs in the country by the end of 2019.
"Amazon proves every day that you can be a fair and responsible employer without a collective agreement," the spokesperson said. "In our fulfillment centers, our wages are at the upper end of what is paid in comparable jobs."
A spokesperson for UNI Global Union, a worldwide federation of service workers unions, told CNN Business that Amazon workers in the United Kingdom, Spain, and Poland were holding protests at the company's facilities to demand better working conditions and higher wages.
Amazon's global sales for Prime Day are expected to hit $5.8 billion over the two days, estimated Coresight Research. Last year, the company generated $3.9 billion on Prime Day, according to Coresight.
Amazon, which raked in $232 billion in sales last year, does not itself specify its revenue on Prime Day.
— Nathaniel Meyersohn contributed to this report.
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