Passengers at German airports face lengthy delays on Thursday after trade union Verdi called for a strike by ground staff as part of wider industrial action over public sector pay.

Verdi on Tuesday called on ground staff, baggage handlers and maintenance staff at almost all of Germany’s big airports to strike during the morning shift on Thursday, which runs until 1300 GMT.

The airport strike is part of wider industrial action by public sector workers, including those driving local transport or running childcare centers, after public sector pay talks failed to produce any sign of a deal.

Lufthansa, Germany’s largest airline, said it expected significant disruption and would announce information on potential flight cancellations and alternative travel arrangements on Wednesday.

Verdi represents around 6,000 public sector airport workers in Frankfurt, Europe’s third-largest hub. Lufthansa said it would have to cancel a majority of its flights from Frankfurt if many workers took part in the action.

“Verdi is once again ensuring that a third party that is not part of the pay dispute, will be hit by the strike,” it said.

The strike will affect Cologne-Bonn, Duesseldorf, Hamburg, Hanover and Stuttgart airports, as well as Munich and Frankfurt.

Trade unions want pay rises of 3.5 percent and an extra 100 euros ($140) per month for some 2.1 million federal and municipal public sector workers. That would amount to a total increase of 6.7 percent, they say.

While the government accepts there will be a pay increase, it is unwilling to meet the demands by the Verdi and dbb trade unions. Interior Minister Thomas de Maiziere has described them as “exorbitant”.

German air travellers could face disruption from other industrial unrest too. Lufthansa pilots voted on Friday to back their demands for better pay and working conditions with industrial action.

Verdi’s call comes after a strike by private sector security staff at Frankfurt airport last month caused dozens of flight cancellations and delayed thousands of passengers.

A third round of public sector pay negotiations is due to take place on March 31-April 1.

(Reporting by Victoria Bryan; Editing by Mark Potter)

Photo Credit: A passenger walks through a terminal during a strike at Frankfurt airport. Ralph Orlowski / Reuters