Aizawl, June 28 (IANS) At least three persons including a Myanmarese national were killed while one was injured after a mound of sand collapsed while they were digging sand in Mizoram's Champhai district, the police said.

A police officer said the mishap happened near Melbuk village when a portion of the sand mound collapsed and the labourers were buried beneath the sand.

The deceased, including the injured, aged between 16 and 20, were engaged in a digging operation in the Tiau river for commercial purposes.

While two people, residents of Mizoram, died on the spot, the Myanmar national succumbed to his injuries on the way to a hospital.

The injured person is now under medical treatment in the Champhai district hospital, the police official said.

Police said that those who were digging river sand for commercial purposes by using excavators breached safety norms.