Berlin - A strike by security staff at eight German airports on Tuesday is causing travel chaos for tens of thousands of travelers.

The ver.di union 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).

In Frankfurt alone where more than 1,000 security staff were participating in the strike, 570 flights were canceled and that across Germany up to 220,000 passengers may be affected.

“Air traffic is severely affected,” ver.di’s Benjamin Roscher in Frankfurt told the German news agency dpa.

“We hope that the employers will finally be responsive to our demands.”

Frankfurt is the main hub for Germany’s biggest airline, Lufthansa. The airline said earlier that passengers with a flight from Frankfurt can rebook for free onto another flight until Jan. 20.

Ver.di said it is still waiting for employers to increase the pay of 23,000 security staff conducting checks and is demanding that their hourly rates rises to 20 euros ($23.10).

Employers association BDLS says this could amount to a 30-percent increase in some cases.

“Again, the trade dispute is being carried out on the backs of hundreds of thousands of passengers, the airlines and many other companies belonging to the German tourism industry,” said Michael Rabe, the general secretary of the Federal Association of the German Tourism Industry.

Last week, strikes across Germany resulted in the cancellation of hundreds of flights.