BERLIN (AP) — A union says security personnel at Germany's Duesseldorf and Hamburg airports will walk off the job Thursday after wage negotiations failed to make any progress.

The ver.di union said in a statement Wednesday that the workers would stage a strike between 4 a.m. and midnight (0200 GMT and 2200 GMT) on Thursday after the latest round of negotiations with employers ended last week without an offer they found acceptable.

Airport workers in recent months have staged several such warning strikes, which are used regularly as a tactic to increase pressure in German wage negotiations.

The union is seeking a roughly 30 percent pay increase for the private security company workers. Employers have offered a 9 percent raise for the airport workers.