Some of Amazon's workers in Europe are protesting against what they call unfair work conditions, in a move meant to disrupt operations on Black Friday.
Labor groups representing workers at Amazon Spain said that around 90 percent of workers at a logistics depot near Madrid joined a walkout Friday. Only two people were at the loading bay, said Douglas Harper of the CCOO trade union confederation.
Amazon challenged the unions' walkout figures, saying in a statement that most staff had turned up for work at the depot.
On a picket line, 38-year-old employee Eduardo Hernandez said the walkout intended to hurt the company financially.
"It is one of the days that Amazon has most sales, and these are days when we can hurt more and make ourselves be heard because the company has not listened to us and does not want to reach any agreement," said Hernandez, who has worked for five years at Amazon.
Unions in Britain said they would stage protests at five sites to complain about safety conditions. Amazon said the safety record at its warehouses is above the industry average.
In Germany, workers walked off the job at Amazon distribution centers in Rheinberg and Bad Hersfeld as part of a years-long push for higher pay, the ver.di union said.
The union argues Amazon employees receive lower wages than others in retail and mail-order jobs. Amazon says its distribution warehouses in Germany are logistics centers and employees earn relatively high wages for that industry.
While Black Friday discounts have traditionally been a U.S. retail event, companies have increasingly been offering discounts in other countries too.
This story has corrected to show that Harper is a trade unionist, not an Amazon spokesman.