At least four children were hurt in a small explosion in front of a school in Kaushambi near Allahabad on Tuesday but it may not be a militant attack, police said.
The blast occurred in a deserted house in Kaushambi.
"During recess some children had gone to a deserted house near the school to play. They may have touched some crude explosive device," M.P. Verma, a senior police officer, told Reuters.
"This does not look like a terrorist attack. A team of bomb experts has gone there."
India has been on high alert after a bomb in the western city of Pune killed 15 people on Feb. 13.
That attack was suspected to have been carried out by home-grown Islamists and was the first major militant strike since the 2008 attacks on Mumbai.