Police on Monday blamed tainted vinegar for causing a mass poisoning that killed at least 11 and sickened about 120 others at a Ramadan meal in northwest China.

A six-year-old was among the dead from the incident that occurred in the village of Sangzhu, near the city of Hotan in Xinjiang Uygur Autonomous Region on late Friday, local police said. One remains in critical condition while the others are out of life-threatening danger after hospital treatment.

The initial probe shows that villagers consumed vinegar from two plastic barrels that previously contained antifreeze at a late night Ramadan meal and felt sick on the next morning. But the toxicity tests have yet to confirm the source of poisoning, police said.

Antifreeze commonly contains a chemical known as ethylene glycol that is toxic to humans, causing symptoms such as diarrhea and vomiting.

The poisoning occurred during the religious period of Ramadan, when Muslims eat in large groups at night after fasting during the day, and police say this is why so many were affected.

More than half of Xinjiang's population of 21 million are Muslims from 10 ethnic groups, including Uygur, Kirgiz, Kazak and Uzbek. During Ramadan, the ninth month of the year in the Muslim calendar, Chinese Muslims refrain from eating, drinking, smoking and sex from sunrise until sunset. Children, the elderly and the weak do not have to fast.

Police are still probing the cause of the poisoning.

China's Ministry of Health reported that at least 45 people died in food poisoning cases across the country in the first six months of 2011, and the majority of the deaths were caused by food tainted by toxic chemicals.

The ministry also reported that most deaths occurred at home. Eleven cases were reported in student canteens in the first half of the year, with 701 sickened but no deaths recorded.