HANGZHOU, April 5 (Xinhua) -- Police in Yongkong, east China's Zhejiang Province, have offered a 50,000-yuan reward hoping it will lead to the arrest of people who deliberately poisoned 57 diners last week.

    Police say someone put rat poison into the breakfast being served at a restaurant in Xixi township.

    The 57 victims including a number of students who felt nauseous and suffered stomachaches after eating breakfast last Thursday. They were hospitalized and were examined by a panel of experts.

    Eighteen people are still in hospital while 39 others were treated and released, doctors said Thursday.

    Also in Zhejiang Province, 36 students were hospitalized Wednesday afternoon suffering similar symptoms after they eating beef soup served for lunch at a snack bar in Cangnan county.

    Test on soup samples showed the students were poisoned by excessive amount of nitrite.

    The students were all out of danger by Wednesday night and some have been discharged from the hospital.

    The investigation into the cause of the food poisoning is still underway.