Nigeria’s newly elected president, Muhammadu Buhari, is vowing to make every effort to free hundreds of girls abducted by Boko Haram militants.

A year after they were taken from a boarding school in Chibok, campaigners are taking to the streets to pile pressure on the government.

“When your voice is taken, you can’t speak. You don’t exist. But our girls exist,” said campaigner Oby Ezekwesili, as she taped over her mouth.

Almost 300 schoolgirls were abducted last April. Dozens escaped, but 219 remain missing.

Led by Abubakar Shekau, Boko Haram is trying to establish an Islamic caliphate.

With help from Nigeria’s neighbours,Niger, Cameroon and Chad, the militants have been forced to retreat from an area the size of Belgium in recent weeks.

Euronews reporter Luis Carballo has been embedded with troops fighting Boko Haram on the frontline.

“The joint operation, particularly Chad’s involvement, is starting to change things on the ground,” said Carballo.

Euronews was wi