Eleven other students were taken to a sub-district hospital in Pampore town - and again three of them were shifted to Srinagar.
The tuition-cum-coaching centre was being run in a private school called 'Falai-e-Millat' public school in Narbal village near Kakapora town.
All educational institutions are closed in the Kashmir Valley these days due to winter recess.
"The exact facts as to what caused the explosion are being ascertained."
An earlier unconfirmed report said the explosion took place when one of the students was fiddling with a grenade he was carrying.
Meanwhile, clashes broke out between security forces and civilian protesters as news about the explosion spread in Narbal village.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)