Fourteen people remained in hospital with symptoms of suspected poisoning after a wedding banquet Sunday in Xining in northwest China's Qinghai Province, said local authorities on Tuesday.

As of Tuesday afternoon, fourteen people were still receiving medical observation, said Yang Zhengping, director with the intensive care unit (ICU) of Qinghai Provincial People's Hospital.

All of them, including an 80-year-old woman, were in stable condition, said Yang.

Twenty-four people were sent to two local hospitals with nausea, diarrhea, abdominal pain or vomiting after attending a wedding banquet in a restaurant in urban Xining on Sunday.

They have been given a preliminary diagnosis of suspected poisoning. Test results are expected to be released in about five to seven days.

The incident is under investigation by local police and health authorities.