The schoolgirls were taken from their hostels by gunmen who raided the Government Girls Secondary School in the town of Jangebe, a high-ranking government official with knowledge of the incident told CNN.

A police officer was killed in the attack, according to the source, who did not want to be named as he did not have permission to speak on record.

“They came on about 20 motorcycles and they marched the abducted girls into the forest,” the source said. “The bandits arrived around 1:45 a.m. and they operated ’til about 3 a.m.

“The sad part is that there’s a military checkpoint that is about four minutes away from the school,” he added.

About 500 students are normally at the boarding school, of whom around 315 were taken by the gunmen. Others managed to flee and return to their hostels, the source said.

A spokesman for the state police told CNN that a detailed statement would be released as they piece together what happened. He declined to comment on the number of students kidnapped.

Later on Friday the force said in a statement that a “heavily-armed” joint search and rescue operation had been launched.

The distraught parents of some of the schoolgirls spoke to CNN on Friday, with one saying her daughter was apparently seized in her pajamas.

“My daughter is among those who were taken away because I saw her things left behind,” Jummai Haruna, mother of Hafsat Abubakar, told CNN.

“I believe she was taken away wearing only her sleeping clothes because I found her hijab and her school uniform.”

“I miss her so much already. Nobody has told me anything about her whereabouts of my daughter. She has always been with me. Her father died when I was still pregnant with her. Now I don’t what to do,” Haruna said.

The dormitory of the Government Girls  Secondary School in Jangebe, Zamfara state, after hundreds of schoolgirls were kidnapped by armed men

Narama Umar’s niece, Asmau Lawali, 14, is also among the missing.

“The government should please help bring our daughters back. There were a lot of parents in the school crying. This is very sad, we want our daughters back,” Umar told CNN.

Another resident, Safiyanu Jangebi, told CNN he heard gunshots at the time of the kidnapping and described how onlookers clashed with the police at the scene.

“There are policemen all over the school, the youths are angry and are now throwing stones at the police. The governor’s wife was also here. They also threw stones at her, chanting ‘Allah will punish you’ and ‘We will not forgive you,'” Jangebi said.

In a statement released on social media Friday, Nigerian President Muhammadu Buhari said the abduction was “inhumane and totally unacceptable.”

“This administration will not succumb to blackmail by bandits who target innocent school students in the expectations of huge ransom payments,” Buhari said in the statement, which was posted by his official spokesperson.

School uniforms still hung inside the deserted school dormitory following the attack

He added: “We have the capacity to deploy massive force against the bandits in the villages where they operate, but our limitation is the fear of heavy casualties of innocent villagers and hostages who might be used as human shields by the bandits.

“Our primary objective is to get the hostages safe, alive and unharmed.”

Secretary-General of the United Nations António Guterres also condemned the attack.

“The Secretary-General calls for the immediate and unconditional release of the abducted children and for their safe return to their families. He reiterates that attacks on schools and other educational facilities constitute a grave violation of the rights of children and human rights more broadly,” his spokesperson said in a statement released on Friday.

In a later tweet, Guterres called the abduction “a heinous violation” of human rights.

Amnesty International said the incident amounted to a “war crime.”

The latest abduction comes barely two weeks after at least 42 people, including students, were kidnapped in a similar raid on a state school in Niger state, in Nigeria’s Middle Belt region. A student was killed in that attack, while 27 students, three teachers and nine family members, were abducted. Their current whereabouts are unknown.

UNICEF Friday expressed concern at reports of the overnight attack.

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“We are angered and saddened and by yet another brutal attack on schoolchildren in Nigeria,” said Peter Hawkins, UNICEF representative in Nigeria.

“This is a gross violation of children’s rights and a horrific experience for children to go through — one which could have long-lasting effects on their mental health and well-being. We utterly condemn the attack and call on those responsible to release the girls immediately and for the government to take steps to ensure their safe release and the safety of all other schoolchildren in Nigeria.”

“Children should feel safe at home and at school at all times — and parents should not need to worry for the safety of their children when they send them off to school in the morning,” said Hawkins.

Many parents are worried about the safety of their children in schools in the north of Nigeria.

In December, at least 300 schoolboys were kidnapped by bandits in Katsina, Buhari’s home state. The students have since been released.

The most prominent of the school kidnapping cases in the country was that of the Chibok schoolgirls who were abducted by Boko Haram in April 2014.