BERLIN — A strike by the ground staff at Germany's Hamburg Airport has caused the cancellation of more than 50 flights.

The ver.di labor union called ground staff out on a one-day strike starting at 3 a.m. Monday. The walkout was announced Sunday evening.

The airport said airlines had canceled 58 of the day's scheduled 388 departures and arrivals at the airport in northern Germany by Monday morning. It said further cancellations and delays couldn't be ruled out.

The union is seeking a pay increase for nearly 1,000 ground staff at the airport, including workers who handle planes, luggage and airport buses. It is seeking a 275 euro ($315) per month raise for all and says management's offer so far is insufficient.