FRANKFURT (Reuters) - Cabin crew representatives warned Lufthansa (LHAG.DE) passengers they face fresh disruption on Tuesday and Wednesday unless the carrier makes concessions in a row over pay and conditions.
Lufthansa canceled almost 200 flights last Friday in an initial strike by flight attendants which stranded 26,000 passengers and cost Germany's biggest airline millions of euros.
The airport, Germany's busiest, was also closed to inbound flights from Europe for several hours due to congestion.
The UFO cabin crew union wants a 5 percent pay increase and guarantees against outsourcing and the use of temporary workers.
Lufthansa is in the midst of a 1.5 billion euro cost-cutting program to combat rising fuel costs and competition from low-cost and Gulf carriers.
The airline has said it will not improve its offer to raise pay by 3.5 percent in exchange for longer hours.
"We will give Lufthansa until Tuesday. Then they must expect more widespread strikes," Nicoley Baublies, the head of UFO, which represents around two-thirds of Lufthansa's 18,000 cabin crew, told German daily Bild.
The union, which has said Frankfurt, Munich and Berlin are all candidates for action, will announce on Monday night where and for how long it intends to strike on Tuesday.
Silvia Quandt analyst Stefan Kick estimated the cost per day of strikes at around 10 million euros ($12.60 million).
Lufthansa said it had a contingency plan for further strikes but gave no details. ($1 = 0.7933 euros)
Reporting by Victoria Bryan and Peter Maushagen; Editing by David Cowell