(AFP) - Anger erupted in a town in remote northeast Nigeria on Thursday after officials fumbled to account for scores of schoolgirls who locals say have been kidnapped by Boko Haram jihadists -- a disappearance reviving traumatic memories of the abducted Chibok schoolgirls.

Police said on Wednesday that 111 girls from the state-run boarding school in Dapchi, in Yobe state, were unaccounted for following a jihadist raid on Monday night.

Hours later, Abdullahi Bego, spokesman for Yobe state governor Ibrahim Gaidam, said "some of the girls" had been rescued by troops "from the terrorists who abducted them".

But on a visit to Dapchi on Thursday, Gaidam appeared to question whether there had been any abduction.

"The girls scattered during the attack, and we can't be sure whether they were lost or taken," he said. "We have no certainty that these boys (Boko Haram) took these girls.

"Nobody saw these girls being taken in vehicles. It is possible some of the girls came across motorists and they gave them a ride to some places."

As news of his comments spread, groups of angry youths set up barricades and burned car tyres in the streets, hurling missiles at the governor's convoy.

Bego's statement had been the first official acknowledgement of an abduction, two days after Boko Haram fighters stormed the remote town in pick-up trucks and a lorry.

The disappearance sparked fears of a repeat of the 2014 mass kidnapping of more than 200 girls from a similar school in Chibok, in neighbouring Borno state.

Initially, the students in Dapchi were reported to have fled with their teachers at the sound of gunfire. Families claimed the authorities tried to cover up the abduction.

A federal government delegation spent less than an hour on the ground at the school meeting Gaidam and military commanders before leaving by helicopter.

Information Minister Lai Mohammed made no direct comment on Gaidam's remarks, but said some students "have phoned from their hiding places... (and) other locations".

He told reporters: "As things develop we will let you know. But we cannot categorically say, 'x number of girls have been abducted'. But we can say that not all have returned."

- 'Devastated' -

Inuwa Mohammed, whose 16-year-old daughter, Falmata, was missing, said he was "devastated by this twist of events" and that his wife fainted on hearing the news and was in hospital.

"I woke up with the strong hope of meeting my daughter and my wife had been making preparations for a warm welcome, only for us to receive this shattering news that all along the story has been a rumour," he added.

The attack will again raise questions about the government's grip on security in remote northeast Nigeria, after nearly nine years of fighting and at least 20,000 deaths.

US State Department spokeswoman Heather Nauert said Boko Haram's "choice of targets including schools, markets and places of worship reflect the brutality of terror organizations."

Residents said fighters dressed in military fatigues and turbans arrived unchallenged, firing weapons and shouting "Allahu Akbar" ("God is greatest").

Safai Maimagani, a herbal medicine vendor, said the militants headed towards the school on the edge of the sleepy farming community.

When they returned, "I heard shrieks of girls from the lorry," he said.

Muhammad Kabo, a tea seller, gave a similar account: "They were here for less than an hour. I heard girls wailing in the truck and it was clear that they abducted some girls from the school."

A school security guard who gave his name as Baa-Koro said the gunmen tried to stop the girls from fleeing and tricked them into believing they had come to rescue them.

"Some of the girls believed them and climbed up into the lorry. Many others just kept running," he added.

President Muhammadu Buhari was elected in 2015 on a promise to defeat the Islamic State group affiliate and has repeatedly maintained they are now a spent force.

But civilians -- especially those displaced by the conflict -- remain vulnerable to suicide attacks and hit-and-run raids.

The Dapchi attack also calls into question how far pledges to improve security at schools have been implemented nearly four years after the Chibok abduction.

Since May last year, 107 of the 219 held since 2014 have either escaped or been released as part of a government-brokered deal.

Security analysts suggested government ransom payments to secure the release of the Chibok girls could have given the under-pressure group an incentive for financing.

© Agence France-Presse