The injured were rushed to nearby medical facilities. Some of them are said to be critical.
According to reports, most of the passengers were asleep and could recover from the impact of the collision as both the vehicles caught fire after the accident.
According to ANI, a total of thirty-seven passengers were on board the bus.
The doctors said the death toll could rise as most of the passengers were severely burn.
CFM District hospital, Dr. B.C. Yadav told ANI, "The bodies were burnt outright to an extent that it is arduous to figure out the gender of the corpses. 15 have been injured and are admitted to Shri Siddhi Vinayak Hospital and one of them will be referred to Lucknow. The death toll is likely to increase."
According to eyewitnesses, some of the bodies have been charred beyond recognition.
The bus belonging to Gonda depot was travelling to Uttar Pradesh's Bahraich from Delhi. The accident took place round about 2:00 a.m
A district official told IANS that the truck driver has escaped. The police were looking for him.
(With inputs from agencies)