A Pakistani schoolgirl shot by the Taliban for championing women's rights has told the United Nations she was attacked because extremists fear the power of education.
Malala Yousafzai, who has been recovering from last year's attack in the UK, told the youth assembly there were millions who had been attacked or killed across the world because of the terrorists' fear of "books and pens".
She called on those present to take up "the weapon of knowledge" in their campaign for access to education for all children around the world.
Friday is Malala's 16th birthday - declared Malala Day - in what was the first public address by the teenager in front of more than 500 youth delegates at the UN headquarters in New York.
As she took to the dais, there was a standing ovation and cheers of delight for the young girl who cheated an assassin's bullet following an attack on her school bus in the Swat valley in north-western Pakistan last year.
In a powerful address, she said: "We realise the importance of our voice when we are silenced and in the same way when we were in Swat, in the north of Pakistan, we realised the importance of pens and books when we saw their guns.
"The saying 'the pen is mightier than the sword' was true. The extremists were, and they are, afraid of books and pens. The power of education frightens them. The power of the voice of women frightens them, and that is why they killed 14 innocent medical students in the recent attack in Quetta."
Malala said Muslim extremists in Pakistan and Afghanistan were "mis-using the name of Islam and Pashtun society for their own personal benefits". She also criticised the use of children for child labour, the practice of forcing young girls to marry and the recent attacks on schools in Nigeria.
Closing her address, she said: "So let us wage a global struggle against illiteracy, poverty and terrorism and let us pick up our books and pens. They are our most powerful weapons. One child, one teacher, one pen and one book can change the world. Education is the only solution - education first."
The event was organised by former prime minister Gordon Brown, now UN Special Envoy for Global Education. UN Secretary General Ban Ki-moon, who also attended the event, called her "our hero, our champion" and accepted a petition with four million signatures demanding education to all.