Verdi, the union representing 33,000 Lufthansa Group ground workers, has rejected the airline’s latest contract offer as “unacceptable.”

The union said Lufthansa offered to increase salaries 1.2% from October and a further 0.5% next year. The offered labor deal would run for 29 months, but would not guarantee jobs, according to Verdi.

Verdi is demanding a 5.2% pay raise for Lufthansa ground workers. It also wants a commitment to safeguard jobs.

No strike dates were given. Lufthansa could not be immediately reached for comment.

Lufthansa is in the midst of a cost-saving program, SCORE, which aims to improve annual earnings by at least €1.5 billion ($2 billion) by 2015. The program includes eliminating 3,500 jobs.

Lufthansa employees represented by Verdi held a one-day strike March 21, forcing the carrier to cancel 700 flights. The parties will continue negotiations April 29-30.