The decision to conduct the one-week strike from November 6-13 was announced in a press conference on Monday by the head of UFO, Nicoley Baublies.
There was no mention of which Lufthansa flights were to be affected.
Baublies added that the strike could still be called off if Lufthansa management countered with a more amenable offer by Thursday afternoon.
UFO has been in talks with Lufthansa over a dispute concerning cuts the company has proposed to cabin crew employee benefits, including pensions. The talks stalled over the weekend as the November 1 deadline for an agreement passed.
The union called the most recent proposal from Lufthansa "completely unacceptable."
In turn, Bettina Volkens, Lufthansa's board member in charge of human resources, saw UFO's decision to go on strike as "unreasonable." The company said it would consider all available legal measures to prevent the strike, including the resumption of talks or arbitration, according to a spokesperson.
jtm/jm (AFP, dpa)