Confirmed A/H1N1 flu cases in Germany have increased to 172 as of Monday, said the country's federal agency for infectious diseases, the Robert Koch Institute.

Among Germany's 16 states, the hardest-hit is North Rhine- Westphalia, with 78 confirmed cases, followed by Bavaria with 27. Only two states, Bremen and Saarland, have not registered any confirmed cases so far.

The most concentrated outbreak of A/H1N1 flu was reported at a Japanese school in Duesseldorf, capital city of North Rhine- Westphalia. The number of children at the school who have tested positive for the A/H1N1 virus jumped to 65 from 46 last Friday, a spokesman of the city said on Monday.

According to the Robert Koch Institute, all A/H1N1 flu infections in Germany have not showed severe symptoms.