It is the latest in a series of recent abductions for ransom in northern Nigeria.
How were the children kidnapped?
An armed group stormed the Salihu Tanko Islamic School on motorcycles, killing one person and abducting three teachers, along with the students, the school's owner, Umar Idris, told The Associated Press.
Niger state officials confirmed the number of kidnapped students in a statement, clarifying uncertainty about the magnitude of the attack.
The number could still rise though, as not all parents have been contacted to confirm that their children are at home, Idris said.
"We have sent out a message asking parents who have not yet reported to the school to do so," Idris added.
Children snatched in front of parents
One parent, Ashiru Adamu Idrisa, told reporters that his three daughters — the youngest just 5 years old — were snatched in front of him.
"What I saw was horrifying," he said. "Right in front of my eyes, my children were taken out."
Idris said the gunmen abandoned some preschoolers along the way because they could not keep pace with the group as they headed into the forest.
"The 11 children were mainly aged between 3 and 4 and they lacked the stamina to keep pace with the gunmen, so they were abandoned on the way," Idris said. They were found hours after the attack.
What is the regional government doing?
The state government told AFP news agency that it was negotiating with the group who took the children.
"We are in touch with the kidnappers to find a way to secure the release of the children. We are negotiating to see how we can arrive at an agreement," Deputy Governor Ahmed Mohammed Ketso said.
"We are also in contact with the parents," he added. "We call on them to be patient. Government is making all efforts to secure the release of the children."