LAGOS- Nobel peace laureate Malala Yousafzai today criticized Nigerian and world leaders for not doing enough to help free 219 schoolgirls kidnapped a year ago by Boko Haram militants.

“In my opinion, Nigerian leaders and the international community have not done enough to help you,” she said in a letter to the teenagers, on the eve of the first anniversary of their abduction.

“They must do much more to help secure your release. I am among many people pressuring them to make sure you are freed,” she added, calling the girls “my brave sisters”.

Islamist fighters kidnapped 276 girls from their school in the remote town of Chibok, in Borno state, northeastern Nigeria, on the evening of April 14 last year.

"We cannot imagine the full extent of the horrors you have endured. But please know this: we will never forget you," Ms Yousafzai said in the letter to the 219 girls.