Eight schoolboys studying in elementary and high school drowned when they went swimming in a river in Vietnam last Thursday.

At about 3 pm on March 21, a group of 10 students from the Huu Nghi Primary and Secondary School in Hoa Binh province went for a swim in the Da River, VN Express reported. They reportedly ended up in a deep hole in the river.

Only two of the group were able to swim back to the shore. The bodies of the children were found at about 4:30 pm, three of them primary school students. The boys were last seen playing football before they jumped into the river.

A local official said there was a deep hole in the river the students may not have known about. In Vietnam, drowning is one of the common causes of child deaths. According to statistics by the World Health Organization, more than 11,000 children drown every year in the country.