Scores of flights have been canceled at Duesseldorf airport after security personnel walked off the job in a one-day strike to press their demands for higher pay.

By midday Monday, the dpa news agency reported 172 starts and landings of 593 planned had been canceled. Some 250 workers staged the so-called warning strike, a tactic used by German unions to increase pressure on employers.

The ver.di union seeks a roughly 30 percent pay increase this year for private security workers, including about 2,000 airport security personnel and 32,000 others in the state of North Rhine-Westphalia. Employers have offered a 9 percent raise.

Ver.di has staged regular strikes this year at the state's Cologne-Bonn and Duesseldorf airports as well as in Hamburg, where it's also seeking a new wage deal.