But a spokesman for Germany's largest airport, Frankfurt, said the token strike had not caused any delays there.

Verdi's leader in the talks, Andreas Sander, said about 1,000 of the 15,000 airport security workers took part in strikes that began between 5 a.m. and 6 a.m. (0400 and 0500 GMT) and lasted until about 9 a.m. (0800 GMT)

"They're crippling the airports," Sander said. The union unexpectedly called for the token strikes late on Sunday to press their demands for better working conditions.

The strikes also affected airports in Berlin, Hamburg, Hanover, Stuttgart, Duesseldorf, Bremen, Cologne/Bonn and Baden-Baden/Karlsruhe. German media reports said Cologne-Bonn had massive delays with long waits at security check-in points.

The union wants fewer limited-term contracts for workers and unified working conditions at all German airports.

Talks with the BDSW employers stalled after four rounds in mid-November, Verdi said. The next round is set for Jan. 15.