The two sides held two weeks of talks, led by mediator Gunter Pleuger, in a bid to resolve a long-running row over pay contracts dating back to 2012 for around 5,400 Lufthansa pilots.

"Despite intensive discussions, an agreement could not be reached," VC said in a statement, adding Pleuger would make a recommendation by Feb. 10.

The two sides will then discuss how to respond to the recommendation.

Lufthansa's pilots have walked out 15 times since early 2014 over dispute with management on topics including pay and early retirement, costing the carrier hundreds of millions of euros in lost profits.

Most recently, they were on strike for six days in November, costing the airline a further 100 million euros ($107.5 million) in profits.

Before the mediation process, the pilots had asked for an average annual pay increase of 3.7 percent over a five-year period back-dated to 2012, which is when their last collective bargaining contract with Lufthansa expired. The pilots say altogether these increases would amount to a rise of nearly 20 percent on current pay.

Lufthansa had proposed an increase of 4.4 percent in two installments in 2016 and 2017, plus a one-off payment worth 1.8 months' pay.

(Reporting by Peter Maushagen; Writing by Victoria Bryan; Editing by Maria Sheahan)