Berlin, Sep 7 (IANS): German pilots' union Vereinigung Cockpit (VC) on Monday said its members would walk out from all long-distance flights operated by Lufthansa on Tuesday, as a long-running dispute over pay, conditions and retirement heats up again.

No VC members will be at the controls between 8.00 a.m and midnight on Tuesday, The Local news portal reported.

All Lufthansa passenger flights, Airbus A380, A330/340 and Boeing 747 aircraft -- meaning all long-distance flights leaving Germany -- will be affected.

"Lufthansa offered twice to re-open talks with VC at the weekend. These only seemed promising at first look. A closer analysis showed, however, that the content was once again free of substance," the pilots wrote in their statement.

A Lufthansa spokeswoman said the company had made a "far-reaching, comprehensive" offer to VC.

However, airlines CEO Carsten Spohr on Sunday evening said "the financial market appreciates it if we remain tough in these labour disputes".

The Pilots have said they have no option but to strike for the 13th time since April 2014 -- at an estimated total cost to Lufthansa of around 300 million euros (about $334 million) -- after repeated attempts to compromise with management have failed.

The main battles have been over raising the age at which Lufthansa pilots can take an early retirement and creating new pay grades for workers in the group's low-cost branches such as Germanwings.

Mediation efforts between the parties fell through in July, while the pilots say their latest offer of an "alliance for growth and employment" with "extensive concessions worth over 500 million euros (about $550 million)" was rejected by bosses.