Ver.di, one of Germany’s largest unions, on Tuesday called a nationwide strike by 12,500 armed drivers and other workers who transport cash to banks and retail outlets across the country after five rounds of unsuccessful wage talks.

The strike will begin on Wednesday and could continue until Friday, depending on progress in the next round of wage talks scheduled for Thursday and Friday, the union’s lead negotiator, Arno Peukes, told Reuters.

“Our message to the employers is clear. If no negotiable offer is presented, the strikes will be expanded,” he said.

Hundreds of money transports will be affected across Germany, potentially leading to serious consequences for retailers and bank machines, which are often empty after the New Year’s holiday, the union said.

Ver.di is pressing employers to boost wages by 250 euros ($290) a month and to bring wages in the former East Germany to levels on a par with those in the West over a two-year period.

Money counters and drivers currently earn 1,800 euros to 2,400 euros per month in the eastern part of the country, compared to 2,200 euros to 2,900 euros in the western part, the union said.