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BERLIN, July 19 (Xinhua) -- Four Hong Kong citizens were injured, including two seriously, in a late night Monday attack on a regional train near Wuerzburg in the southern German state of Bavaria, the Chinese Consulate General in Munich confirmed on Tuesday.

A refugee wielding ax and knife wounded a total of five passengers on late Monday night, Bavarian Interior Minister Joachim Herrmann told German ZDF public television on Tuesday morning. Most victims were Chinese tourists, among whom two were critically wounded.

Herrmann said the man, identified as a 17-year-old Afghan asylum seeker, was shot dead while trying to attack the police.

The police reported finding a "hand-painted Islamic State (IS) flag" in the asylum seeker's room.

However, it is currently not certain whether the act was motivated by Islamic extremism. The police are still investigating this element, according to the minister.

Chinese Consulate General in Munich has released security bulletin for Chinese citizens advising them to be vigilant about their safety.