The youngest Nobel Peace prize winner Malala Yousafzai celebrated her 18th birthday on Sunday by opening a school for Syrian refugee girls in Lebanon.

Malala, who turns 18 on July 12, was shot by Taliban militant in 2012, according to BBC. She won the 2014 Nobel Peace Prize along with Indian child rights campaigner Kailash Satyarthi.

"I am honored to mark my 18th birthday with the brave and inspiring girls of Syria. I am here on behalf of the 28 million children who are kept from the classroom because of armed conflict. Their courage and dedication to continue their schooling in difficult conditions inspires people around the world and it is our duty to stand by them," Malala said in a statement published on Malala Fund's blog.

The "Malala Yousafzai All-Girls School" in Lebanon's Bekaa Valley near the Syrian border will provide quality secondary education to more than 200 Syrian girls living in informal camps and out of school, according to a statement issued by the Malala Fund.

The Pakistani girl's rights campaigner called for world leaders to "invest in books instead of bullets." "Today, on my first day as an adult, on behalf of the world's children, I demand of leaders - we must invest in books instead of bullets," she said in her speech at school opening, according to The Week.

She also criticized world leaders' response to Syrian refugee crisis.  "On this day, I have a message for the leaders of this country, this region and the world - you are failing the Syrian people, especially Syria's children. This is a heartbreaking tragedy - the world's worst refugee crisis in decades," she said.

Lebanon has given refuge to nearly 1.2 million Syrian refugees, reported AFP. Out of the 1.2 million refugees, 500,000 are school-age children, and only a few of them are getting an education.