Some of Germany's largest and busiest airports are facing a possible strike by security staff on Tuesday.
The German trade union Verdi on Sunday expanded the call for a strike to include Munich and Hamburg airports in addition to the country's largest airport in Frankfurt.
One-day walkouts are also expected Tuesday at the smaller Hannover, Bremen, Leipzig-Halle, Dresden and Erfurt airports.
The union is demanding that security staff get paid a minimum of 20.00 euros ($23.10) per hour. Security companies say that amounts to a prohibitive 30 percent raise in some cases.
Last week, a strike by security staff forced the cancellation of more than 640 flights at Duesseldorf, Cologne and Stuttgart airports.
Lufthansa, the country's largest airline, has said it anticipates a "significant" impact on flights Tuesday.