Surveillance shows the 3 missing children in the eastern Chinese province of Zhejiang. [Photo: jinbaonet.com]

A massive search is entering its 3rd day for 3 missing children in the eastern Chinese province of Zhejiang.

More than 4-thousand people, including 10 specialized search teams, are looking for a 7-year-old boy and two girls, aged 8 and 12.

They disappeared from their local village in Pujiang County, on the northern outskirts of the city of Yiwu, around noon on Tuesday.

They were last seen on surveillance video at around 6:00pm that day on a bridge at the entrance to the village where they live.

The search area currently spans around 30-square kilometers.

Authorities have not said what led to the children's disappearance.

However, police helicopters have dropped bags containing food, warm clothes and water in the area, suggesting the children may have run away from home.

Divers have searched a local reservoir but have found no trace of the children.

Messages about the missing children have been spreading on social networks across China, with the hope someone outside the area may have information which leads to the children.