Sick students are being treated at a local hostpital in Yulin city of Shaanxi Province on April 22, 2011. [Xinhua]

At least 251 pupils fell ill after drinking milk made by the Mengniu Dairy Company at a school in Shaanxi Province on Friday, according to media reports.

Sixteen students from the city of Yulin showed signs of illness on Friday morning including fever, abdominal pain and diarrhea after drinking the milk provided to Yuhe Town Central Primary School, said a Yuyang district government spokesman.

Some 178 students were hospitalized for observation by late Friday night, the spokesman said.

None of the children showed any other abnormal signs after a day's care, according to the spokesman late on Friday night.

An investigation has found that all the sick students had drunk milk made in a factory in Baoji, Shaanxi.

Previously they had drank Mengniu milk from Hohhot, the Inner Mongolia Autonomous Region.

The school's milk stocks were sealed off as Mengniu staff workers arrived to assist the investigation.

Mengniu milk was authorized for students by the Yulin education bureau.

Some 649 bags of milk were delivered to students on Friday and 136 sacks have since been recalled.