Thousands of Amazon workers across the UK, Europe and the US have gone on strike in protest over pay and working conditions during the ecommerce giant’s event ‘Prime Day’ in which Amazon offers its customers discount deals. The two-day event starts today.

According to UK-based trade union GMB, which represents Amazon workers in the UK, the union will hold demonstrations outside Amazon fulfilment centres (warehouses), including Rugeley, Swansea, Peterborough, Warrington, Coventry, Doncaster and Milton Keynes.

“We’re staging protests across Amazon sites up and down the country this Prime Day,” Mick Rix, GMB National Officer, said. “The conditions our members work under at Amazon sites across the UK are appalling.”

GMB said that since 2015/16, more than 600 reports have been made from Amazon warehouses to the Health and Safety Executive (HSE).

Reuters reports that across Germany, more than 2,000 workers at seven Amazon sites across the country have gone on strike over pay for at least two days.

Amazon has faced a long-running battle with unions in Germany over better pay and conditions for logistics workers and collective bargaining arrangements.

“While Amazon fuels bargain hunting on Prime Day with hefty discounts, employees are being deprived of a living wage,” German union Verdi’s retail specialist Orhan Akman said in a statement.

An Amazon spokesman said the company was a fair and responsible employer even without having a collective agreement in place, adding: “In our fulfillment centers, our wages are at the upper end of what is paid in comparable jobs.”

In the US, workers at Amazon are also planning to stage a walk-out in protest.

Last week, both the UK and France announced that it would impose a digital services tax on tech firms such as Amazon.