With the announcement, Lufthansa joins other major European airlines such as British Airways owner IAG and easyJet in warning on profit as a result of political and economic uncertainty dampening travel demand.
The group also released preliminary results for the first half of 2016, saying sales fell to 15.0 billion euros ($16.50 billion), down from 15.4 billion in the same period last year. First-half adjusted EBIT rose to 529 million euros, up from 468 million last year.
Lufthansa also now expects to increase the amount of flying it does this year by 5.4 percent, instead of a previous target of around 6 percent.
Analysts are looking for details of how attacks in France, Belgium and Turkey are impacting demand when IAG, Air France-KLM and Lufthansa all release full results over the next two weeks.
Lufthansa is scheduled to release full-year results on Aug. 2.
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