Malala Yousafzai, the Pakistani girl shot by the Taliban, has told the UN that books and pens scare extremists, as she urged education for all.
Speaking on her 16th birthday, Malala said efforts to silence her had failed.
She was shot in the head on a school bus by Taliban gunmen because of her campaign for girls' rights.
The speech at the UN headquarters in New York was her first public address since last October's incident in Pakistan's north-western Swat valley.
Malala has been credited with bringing the issue of women's education to global attention. A quarter of young women around the world have not completed primary school.
'Afraid of women'
After the shooting, Malala was flown from Pakistan to the UK for treatment, and now lives in Birmingham, England.
Amid several standing ovations, Malala told the UN on Friday that the Taliban's attack had only made her more resolute.
"The terrorists thought that they would change my aims and stop my ambitions," she said, "but nothing changed in my life, except this: weakness, fear and hopelessness died. Strength, power and courage was born."
She continued: "I want education for the sons and daughters of the Taliban and all the terrorists and extremists."
Malala - who is considered a contender for the Nobel Peace Prize - said she was fighting for the rights of women because "they are the ones who suffer the most".
"The extremists were, and they are, afraid of books and pens," added Malala, who was wearing a pink shawl that belonged to assassinated Pakistan leader Benazir Bhutto. "They are afraid of women."
She called on politicians to take urgent action to ensure every child has the right to go to school.
"Let us pick up our books and pens," Malala summed up. "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."
A passionate campaigner for female education, Malala addressed more than 500 students at a specially convened youth assembly.
UN Secretary General Ban Ki-moon also addressed Friday's session, calling Malala "our hero".
The schoolgirl, who set up the Malala Fund following the attack, presented a petition of more than three million signatures to the UN secretary general demanding education for all.
Former British Prime Minister Gordon Brown opened the session, telling the youths gathered they were a "new superpower" in the world, and appealing to them to help overcome obstacles to accessing education.
The event, described by the UN as Malala Day, was organised by Mr Brown, now the UN Special Envoy for Global Education.
He said: "Getting every girl and boy into school by 2015 is achievable.
"Malala says it is possible - and young people all over the world think it is possible," he said.
Aid agencies say that female access to education in Pakistan is a particular problem.
They say that the country ranks among the lowest in terms of girls' education enrolment, literacy and government spending.
Unesco and Save the Children released a special reported ahead of Malala's speech.
It found that 95% of the 28.5 million children who are not getting a primary school education live in low and lower-middle income countries: 44% in sub-Saharan Africa, 19% in south and west Asia and 14% in the Arab states.
Girls make up 55% of the total and are often the victims of rape and other sexual violence that accompanies armed conflicts.