NANNING, May 22 (Xinhua) -- A man was detained for spreading on-line rumors about earthquakes in southern China's Guangxi Zhuang Autonomous Region, local police confirmed on Thursday.

      A post saying that quakes of at least magnitude 7 would hit northwestern Shaanxi and Gansu provinces within two weeks caught the eyes of police in Beihai City of Guangxi early on Tuesday.

      The next day, the city's web police confirmed the writer of the post to be a local resident surnamed Ning, 21.

      Ning admitted that he had received an instant message on Tuesday about the rumor and he felt it was "interesting," so he posted it on his favorite website.

      He was sentenced to three days in police custody.

      As of Wednesday, police across China had reported 55 similar cases and detained 13 people.

      Under Chinese law, information on earthquakes should be issued by the authorities of provinces, municipalities or autonomous regions. One who spreads rumors about dangers or diseases can be sentenced to up to five days in custody or fined up to 500 yuan (71 U.S. dollars).