Gunmen kidnapped six schoolgirls and two staff members from a boarding school in northern Nigeria on Thursday, police said.

The girls and staff were taken in the early morning from a school called Engravers College in a remote area near the village of Kakau Daji in Kaduna state, said the police.

It was not immediately clear who had taken them. While the militant Islamist group Boko Haram and a branch of ISIL are active in northern Nigeria, kidnappings by other armed groups are also rampant — mostly for ransom.

It's said that abductions for ransom are common in Nigeria and the highway from the capital Abuja to the city of Kaduna has seen a surge in attacks by armed criminals, but raids on schools are rare.

"The command is doing everything possible to secure the release of all the victims unhurt," a police statement said.

About 100 of the more than 270 schoolgirls abducted by Boko Haram from the town of Chibok in 2014 remain in captivity. Last week, police in the city of Kaduna freed hundreds of men and boys from a purported Islamic school where they had been beaten and abused.