The German pilots' union will extend its strike at Lufthansa into Wednesday after a walkout already planned for Tuesday in a long-running dispute over pay, benefits and cost cuts.

Tuesday's strike, the 13th in 18 months, affects long-haul passenger and cargo flights out of Germany from 0600 GMT (2 a.m. EDT) to 2159 GMT (5.59 p.m. EDT) on Tuesday, while Wednesday's 24-hour strike targets short-haul Lufthansa and Germanwings flights, it said on Monday.

Lufthansa said it would operate 90 out of about 170 planned long-haul flights for Tuesday and all seven cargo flights thanks to pilots volunteering to work. It expects several hundred flights to be canceled on Wednesday, when it has 1,350 short-haul flights planned.

Lufthansa is trying to cut costs as it battles to maintain market share against budget rivals such as Ryanair (RYA.I).

Relations between management and the Vereinigung Cockpit (VC) union, which represents around 5,000 Lufthansa and Germanwings pilots, broke down again last week. The union has offered concessions, including increasing the average retirement age to 60 and looking at ways to bring costs down to a level comparable with easyJet.