BERLIN -- A union has called on security staff at eight German airports, including Frankfurt, to walk off their jobs all day Tuesday in a pay dispute.

       Monday's call by the ver.di union sets the stage for another round of disruption after walkouts at several airports last week.

       Ver.di called private security staff out on strike at Frankfurt, Germany's busiest airport, as well as Berlin, Bremen, Hamburg, Hannover, Stuttgart, Duesseldorf and Cologne-Bonn, news agency dpa reported.

       Fraport, which operates Frankfurt Airport, said that no passengers due to start their journeys at the airport will be able to board there.

       The warning strikes come before a fifth round of talks between the union and employers set for Thursday.