Nigeria on Saturday marked four years since Boko Haram abducted more than 200 schoolgirls from the remote town of Chibok, with renewed calls for their release and that of thousands of others seized in the bloody conflict.
A total of 219 girls were taken from the Government Girls Secondary School in the remote town in Borno state on the evening of April 14, 2014 and have become an enduring symbol of the Islamist insurgency.
Four years on, 112 are still being held.
On Friday night, about 100 people attended a vigil in Nigeria's biggest city, Lagos, under a busy flyover whose pillars are now adorned with brightly painted murals of the missing girls.
"We are here to show (the) government that we are still missing our sisters," Zakaria Galang, a brother of one of the students who is yet to return, told AFP.
Further events are planned in the capital, Abuja, on Saturday.
'All hope is not lost'
Nigeria's president in 2014, Goodluck Jonathan, was heavily criticised for his response to the abduction but the man who replaced him, Muhammadu Buhari, has had more success.
Since 2016, 107 girls have been found, released or escaped as part of a government deal with Boko Haram and the administration has said back-channel talks are ongoing for further releases and a possible end to the wider conflict.
Another activist, Habiba Balogun, said she hoped that would happen after nearly nine years of violence that has left at least 20,000 dead and made more than 2.6 million homeless.
"The government has said that they are ready to negotiate; they want to bring this nightmare to an end," she said.
Buhari pledged to the Chibok girls' parents that their daughters "will never be forgotten or abandoned to their fate" despite the time that had passed.
The former military ruler has repeatedly claimed Boko Haram was virtually defeated but while there have been clear army gains, security threats remain.
In February, fighters loyal to a Boko Haram faction headed by Abu Mus'ab al-Barnawi seized 112 schoolgirls and one boy from the town of Dapchi, in Yobe state.
One hundred and seven were returned in mid-March. Five reportedly died, while one girl -- the only Christian in the group -- is still being held.
Buhari said the return of so many students from Dapchi and Chibok "should give confidence that all hope is not lost" and showed the government was "doing its very best".
There had been "unexpected setbacks" in talks because of infighting within Boko Haram.
But he added: "We will continue to persist, and the parents should please not give up. Don't give up hope of seeing our daughters back home again."
Boko Haram has used kidnapping as a weapon of war during the conflict, seizing women and girls to act as sex slaves or suicide bombers, and men and boys to fight.
The Unicef said this week more than 1,000 children had been verified as abducted in northeast Nigeria since 2013, although the real figure is estimated to be much higher.
Amnesty International's Nigeria director, Osai Ojigho, said the Chibok abduction was a small part of a bigger issue.
The government needed to deliver "meaningful action on behalf of all these victims of Boko Haram's crimes".
"Far more support must also be provided for past victims," she said, proposing a register for abducted people.
The International Crisis Group meanwhile said the copycat abduction in Dapchi showed more needed to be done to protect schoolchildren in the restive region.
"The abductions illustrate that Boko Haram remains a menace to swathes of northeast Nigeria," it added in a report published on Thursday.
"They throw into doubt the government's claim to have defeated the movement; instead, insurgents may be newly emboldened to keep fighting.
"The kidnappings cast a pall over education, particularly of girls, and thus the prospects for socio-economic development of the region."
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