Nobel Peace Prize winner Malala Yousafzai has launched a scathing attack on the international community, for not doing more to help free more than 200 Nigerian schoolgirls from Boko Haram.

The Islamist group took the 276 girls from a boarding school in the village of Chibok, in Borno state, north Nigeria, on April 14th last year.

Abubakar Shekau, the group's leader, has threatened to sell the girls "on the market" and some of those kidnapped have reportedly already been trafficked to neighbouring Chad and Cameroon.

There are also reports some of the girls have been sold as brides for as little as €8.50.

Nigeria's President Goodluck Jonathan has been criticised for his handling of the incident and his speed at which there was a response.

Closer to home, protests have previously been held outside the Nigerian embassy in Dublin, with protesters calling for the safe return of the missing girls.

Writing on the Malala Fund website, Ms Yousafzai said: "As we mark this tragic 300th day of captivity for hundreds of kidnapped Nigerian schoolgirls, I call on people everywhere to join me in demanding urgent action to free these heroic girls."

"Nigerian leaders and the international community can and must do much more to resolve this crisis and change their weak response to date."

She adds: "If these girls were the children of politically or financially powerful parents, much more would be done to free them. But they come from an impoverished area of northeast Nigeria and sadly little has changed since they were kidnapped."

She said that politicians running for office in the upcoming elections in Nigeria "should not only demonstrate their empathy but finally take some responsibility for this tragedy."

"These young women risked everything to get an education that most of us take for granted. I will not forget my sisters. We cannot forget them. We must demand their freedom until they are reunited with the families and back in school, getting the education they so desperately desire," Ms Yousafzai added.