Nigeria’s Boko Haram jihadist rebels have released a video purportedly showing some of the more than 300 schoolboys abducted last week from a government boarding school in the northwestern town of Kankara.

In the more than six-minute-long video, the students’ captors tell one boy to repeat the kidnappers’ demands that the government call off its troops and aircraft hunting for them.

A voice can be heard telling the boy what to say from behind the camera.

The boy is clearly speaking under duress.

The boy says that they were kidnapped by a gang directed by Boko Haram factional leader Abubakar Shekau.

He said some of those kidnapped had been killed.

The kidnappers directed the children to ask for ransom money.

The video circulated widely on WhatsApp and first appeared on Nigerian news website HumAngle, which often reports on Boko Haram.

Earlier on Thursday (local time) one of the schoolboys who managed to escape told how he slipped away from his captors.

Usama Aminu, 17, told the Associated Press about the attack on the school in Nigeria’s northwestern Katsina State in which men armed with AK-47 rifles abducted more than 300 students from the boys’ school.

It was late at night last Friday when the students heard gunshots, at first thinking they had come from the nearby town.

As soon as he and the other students at the Government Science Secondary School in Kankara realised there was a raid on the school, they scrambled out of their dormitory and scaled the school’s fence in the pandemonium.

But Aminu was still not safe.

“After we scaled the fence, we were hearing voices that we should come back,” he said.

The boys returned “thinking they were police officers. Unknown to us it was the bandits. They then gathered us at a spot. That was when we realised they were bandits, wearing military uniform,” he said.

“We walked through the night in the bush and at sunrise they found a place and asked us to sit down,” Aminu said.

Aminu, who suffers from sickle cell anemia, recently transferred to the Government Science Secondary School to be closer to his family and medical care for his condition.

In response to the abductions, Nigeria launched a rescue operation in which the police, air force and army tracked the kidnappers to their hideout in the Zango/Paula forest.

The attack has prompted an outcry in the west African country against the government for not doing enough to stop attacks on schools in the north.

“When the bandits heard the sound of the helicopter hovering above they asked us to lay down under the large trees with our face to the ground,” Aminu said.

During their hike, Aminu said they met young boys in their teens, armed with guns.

He said some were younger than him.

Exhausted from the trek, Aminu held onto the shoulders of two friends “as the bandits continued to flog people from the back so that they can move faster”.

After dark, the boy decided to recite passages from the Koran.

It was then that he managed to slip away unnoticed into the night and hide in a mosque.

A local resident eventually found him coughing and offered him a change of clothes so that he could leave his school uniform behind, he said.

He returned home at 11pm on Sunday.

His father, Aminu Ma’le, told AP he was relieved but still worried for the others.

“I cannot celebrate alone because of the other boys still missing,” said the father.

Katsina State governor Aminu Bello Masari said that 17 boys have been rescued since the attack, including 15 by the military, another by police and one boy found roaming in the forest who was brought in by residents.

In April 2014, Boko Haram kidnapped more than 270 schoolgirls from a government boarding school in Chibok in northeastern Borno State.

About 100 of those girls are still missing.

-AAP