TOKYO - Japanese Prime Minister Yukio Hatoyama on Saturday commended Chinese authorities for detaining a suspect in a dumpling poisoning case, expressing hope the development will help deepen bilateral relations.

In a written statement, according to Kyodo News Agency, Hatoyama said he hopes "further progress will be made" in digging deeper into the case.

Traces of methamidophos were found in the frozen dumplings, produced in China, and sickened 10 people, of three families in Chiba and Hyogo prefectures between December 2007 and January 2008. Nine were hospitalized, the report said. Methamidophos, a highly toxic organophosphate insecticide, is used in great quantities in ricefields in China.