All injured have been admitted to Kushinagar district hospital for treatment.
The death toll is expected to rise. All students are said to be from Divine Public School.
Uttar Pradesh Chief Minister Yogi Adityanath condoled the death of the children and announced an ex-gratia of Rs two lakh each to the deceased's family. "An accident relief medical train from Gorakhpur has been dispatched to the site", he said.
The train was on way to Gorakhpur from Siwan.
Authorities have ordered an inquiry into the accident.
The Uttar Pradesh government will take a strict action against the people responsible for the incident and required arrangements shall be made to avoid any similar incidents in the future, as assured by Chief Minister Adityanath.
Reports state that a few moments before the collision, the driver was warned of an "impending collision", however, he failed to pay heed and apparently drove on, leading to the death of 13 of the 18 passengers in the van including himself.
UP CM Yogi Adityanath rushed to the accident spot and told the media that the tragedy happened due to the driver's negligence. The accident took place at a rail crossing in Dudhi near Kushinagar town.
"I have met the family members of the victims and both the state government and Railways will extend financial help".
Gorakhpur Divisional Commissioner Anil Kumar has been asked to probe the incident. The gate mitra tried to stop the van driver but he didn't stop and his van somehow stopped at the track.
In India, there was a new road accident which claimed the lives of 13 children, and another seven were injured. He had earphones on and there are questions about his age too. There are rules in place and inquiry will be conducted as to why they were not followed. Chief Minister has also announced an ex-gratia of 2 lakh rupees to the next of the kin of those killed in the accident.