The incident occurred at Gorgama village while it was raining heavily in the afternoon, they said.
"All the people were working in the agricultural fields and grazing their cattle when the rains started. They took refuge beneath a big tree to save themselves from getting drenched. Suddenly the thunderbolt struck the tree," Piyush Kant, Deputy Superintendent of Police, Belhar said.
The deceased have been identified as Rupesh Kumar (15), Prakash Rajak (10), Shankar Yadav (16) and Mahesh Yadav (17). All of them were residents of Gorgama village.