Nigerian security forces stepped up efforts on Saturday to rescue dozens of students who were abducted from their hostels in northwestern Kaduna state in the latest attack on schools, police and officials said.

Gunmen stormed the Federal College of Forestry Mechanisation in Mando at the outskirts of the state capital, Kaduna city, late Thursday and took 39 students away while the military rescued 180 after a fierce battle.

"A combined team of police, army and other security forces are in a frantic search for the kidnapped students," state police spokesman Mohammadu Jalinge told AFP.

"We are combing the surrounding forests and bushes with a view to freeing the hostages. Very soon, it will be over for the bandits," he said.

Jalinge said the gunmen have not made contacts with the authorities.

The Kaduna college was said to have some 300 male and female students -- mostly aged 17 or  older -- at the time of the attack. 

State commissioner for internal security Samuel Aruwan also said the authorities were hunting the attackers. 

"An operation for the students' rescue is underway by security personnel from the army, air force, police and DSS (secret police)," Aruwan told AFP.

"The security personnel are working diligently to track the kidnapped students," he added.

Distraught parents, relatives and sympathisers have been arriving at the school for news.

Heavily-armed gangs in northwest and central Nigeria have stepped up attacks in recent years, kidnapping for ransom, raping and pillaging.

The gangs have recently turned their focus to schools where they kidnap students or schoolchildren for ransom -- Thursday's was at least the fourth such attack since December.

Mass kidnappings in the northwest are complicating security challenges facing President Muhammadu Buhari's security forces who are also battling a more than decade-long Islamist insurgency in the northeast.