A 40-year-old mentally-ill man Friday hacked his two children to death and critically injured the other two before shooting himself in Bhimnagar district of Uttar Pradesh, around 275 km from here.
Police said the assailant had a "psychiatric record."
The man, identified as Kailash, got up early in the morning and attacked his four sleeping children with a sharp farming tool.
By the time his wife could overpower him, he had killed his daughter and son, aged 12 and 14. Two other children - 16-year-old Parveen and 14-year-old Dinesh Dinesh - were critically injured in the assault, according to police.
The wife told police that after carrying out the assault, the man took out a country-made pistol and shot himself. He died on the spot.
The four children were rushed to the Aligarh city hospital, where two of them were declared dead, while the other two were battling for their lives, police said.
The wife of the assailant told police that her husband had undergone psychiatric treatment many times in the past.