Gunmen have kidnapped more than 50 children from three schools in the same town in north-eastern Nigeria, teachers and parents have told the BBC.

Most of those missing are aged between two and five years old.

Eyewitnesses who saw the attacks on Friday morning in Mussa, Borno state, say the suspects used the children as human shields while fleeing on motorbikes, preventing security forces from opening fire.

No group has claimed responsibility for the attacks. Government officials have not responded to the BBC's requests for comment, but a press statement issued on Saturday by Senator Ali Ndume of Borno South said at least 42 children had been abducted from two schools.

The kidnappings took place at the town's Government Day Secondary School, Mussa Central Primary School, and State Universal Basis Education Board (SUBEB) Secondary School.

Some reports suggest the attacks bore the hallmark of Boko Haram - the Islamist group vying for control over the region against its rival faction, Islamic State West Africa Province (Iswap).

Nigeria is currently grappling with a spate of mass abductions by a range of culprits.

Locals in Borno state have endured decades of insecurity. These latest attacks have prompted some residents of Mussa to flee the area.

Yet traumatised parents have told the BBC they feel they have no choice but to wait in anguish for news about their children.

One man, who did not want to be named for fear of reprisal, said his wife was inconsolable after their six-year-old daughter was snatched away by the gunmen.

Abdu Dunama, headmaster of Mussa Central Primary School, described hearing gunfire before armed men stormed the school and rounded up children.

He said 34 children - mostly nursery pupils aged five and under - were seized by the attackers from their classrooms.

The suspected militants arrived at the schools on motorcycles soon after troops on patrol left the town, according to residents.

"[It was] immediately after they left, it was not up to 30 minutes after," said Bukar Buba, whose daughter was taken.

Witnesses said the gunmen fired sporadically, forcing residents to run for cover. Many parents watched helplessly from a nearby hill as their children were loaded onto motorcycles and taken away.

Some older students managed to flee into nearby bushes during the chaos, according to residents.

The largely farming community - already struggling economically - is now appealing urgently to the government to help secure the safe return of the children.

Dunama, who is in touch with security forces, says troops are currently on the ground and continuing efforts to track the abductors.

Additional reporting by Makuochi Okafor