Berlin-Brandenburg airport is suspending all passenger traffic on Wednesday due to a strike, affecting 445 flights and about 57,000 passengers, the airport’s operators announced on Monday.

The announcement comes after the Verdi trade union called a strike over an ongoing pay dispute.

The union said on Monday that it would hold the walkout as a result of employers’ “refusal to put forward a proposal open to negotiations” amid collective bargaining negotiations.

The union is negotiating with airport management, seeking a salary increase of 6% or at least €250 ($287) in pay raises for its 2,000 employees under a new collective agreement set to run for 12 months.