BERLIN (AP) — Flights across Germany are facing disruption after security staff at eight airports went on strike over pay.

The ver.di union on Tuesday called on staff at airports including Frankfurt, Hamburg, Hannover and Bremen to walk off the job between 2 a.m. and 8 p.m. local time (0100 and 1900 GMT).

German news agency dpa is reporting that in Frankfurt alone 570 flights will be canceled and that up to 220,000 passengers may be affected.

Ver.di said it is still waiting for employers to increase the pay for the 23,000 security staff conducting checks and is demanding that they rise to 20 euros ($23.10) an hour.

Strikes last week across Germany resulted in the cancellation of hundreds of flights.