An unknown person sprayed a suspected ‘irritant gas’ at a check-in counter of Frankfurt International Airport.

Six people have been injured, police confirmed. People affected by the substance are being treated for inhalation and eye injuries.

The incident took place at Frankfurt Airport’s Terminal 1 on Monday afternoon, German media reported. Passengers at a check-in counter complained about eye irritations, prompting the airport to dispatch emergency units.

“6 persons are slightly injured, cause unknown, the investigation is underway,” law enforcement announced on Twitter.

A number of counters were temporarily closed, Focus magazine reported.

There is no information on whether the incident is terrorism-related.

According to Bild newspaper, the incident was dealt with in 16 minutes.

Frankfurt Airport announced on Twitter the check-in counters are now open and operating as usual.

Frankfurt Airport, one of the busiest and largest in Europe, previously had another incident in Terminal 1. On Saturday evening, federal police detained a 37-year-old man who claimed he was carrying an explosive device in his luggage, DPA news agency reported.

The terminal was partially evacuated and the entrance cordoned off, but examination of the man’s luggage only revealed computer parts and a small fuel bottle for camping.

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