Lagos, Nigeria (CNN) -- Police in Nigeria have confirmed that the 15 schoolchildren whisked away by kidnappers earlier this week were all Nigerian nationals.
Four gunmen boarded a school bus carrying the nursery and primary school children from Abayi International School in southeastern Nigeria's Abia state and took the children away.
There were questions as to whether the youths were foreigners because they attended the international school. Police are not releasing the identities of the kids, and don't know their whereabouts.
The kidnappers contacted the children's school, located near the city of Aba and demanded 20 million naira, or around $130,000.
Just after the incident, authorities said the bus driver and the school teacher who were on board were in police custody and helping security forces.
Abia state is often referred to as the "kidnapping capital" of Nigeria since abductions occur there on a weekly basis.
Schools, banks and businesses have closed in the area because of the rampant insecurity and dangers posed by kidnappers.
The problem began after armed youths began to attack oil facilities and kidnap expatriate oil workers in Nigeria's southern oil-producing region.
While kidnappings began as a political statement, they quickly deteriorated into a ransoms and money-making business.
As oil companies increased security for their staffs, Nigerians unable to afford security -- such as the aged and babies -- became targets.
A story in one local newspaper described how kidnappers, using a small bus, grabbed random people off the streets until they were chased by the police. The kidnappers crashed during the hot pursuit and everyone died.
Nigeria's President Goodluck Jonathan has condemned what he calls "utterly callous and cruel kidnapping" and ordered the Inspector-General of Police and heads of other security agencies "to take all necessary steps to rescue the abducted children and return them safely to their parents."
But many such promises have been made in the past and insecurity in Abia has only worsened.
And the little information coming out from police in their search for 15 children highlights the challenges they face in trying to crackdown on the issue at large.