A man threatened an attack on a German high-speed train in western Germany and lightly injured several people before he was detained in the town of Siegburg near Bonn, police said late Thursday.

So-called airsoft firecrackers exploded on an Intercity Express (ICE) train travelling from Cologne to Frankfurt, a police spokeswoman told dpa.

According to the spokeswoman, the suspect had locked himself in a train toilet. German tabloid Bild reported that he had thrown the firecrackers into the corridor.

Police said several people suffered light, superficial skin injuries. The train was evacuated. There was initially no information on how many passengers were on board.

The man was detained at Siegburg station, the spokeswoman said, adding that he had a knife in his backpack.

The Koelner Stadt-Anzeiger newspaper reported that the person was masked. The background to the incident remained unclear.

German rail operator Deutsche Bahn confirmed a police operation but gave no further details.