Peshawar: Nobel laureate and education activist Malala Yousafzai has strongly condemned the burning of 12 schools, half of them all-girls', in Pakistan.

She said "extremists" have shown that a "girl with a book" frightens them the most.

The schools were burnt down late on Friday by unidentified assailants in Pakistan's Gilgit-Baltistan, triggering protests by local residents who sought safety for educational institutions.

The police have arrested ten suspects. Six new arrests have been made, while were arrested earlier taking the total number to 10, Gilgit Biltistan government spokesman Faizullah Firaq said. He added that the suspects were being interrogated at Darul Tangeer police station.

"The extremists have shown what frightens them most - a girl with a book," Malala, 21, said in a tweet.

She also called for the rebuilding of the damaged schools in Chilas town, about 130-km from Gilgit.

"We must rebuild these schools immediately, get the students back into their classrooms and show the world that every girl and boy has the right to learn," Malala tweeted.

Imran Khan, who is set to become Pakistan's new Prime Minister, also condemned the attack, calling it an "unacceptable" act.

"Shocking & condemnable torching of schools in GB, more than half of them girls' schools. This is unacceptable and we will ensure security for schools as we are committed to focusing on education, especially girls' education which is integral to Naya Pakistan," Khan said in a tweet.

Malala, who won the Nobel Peace Prize in 2014, was shot by the Taliban in 2012 for promoting girls' education in the Swat Valle.

Meanwhile, chief secretary of Gilgit-Baltistan Babar Hayat Tarar visited the ruined schools on Saturday and directed the officials to repair the buildings.

Girls' schools are often attacked in the northern areas of Pakistan. In December 2011, at least two schools were partially damaged in low-intensity explosions in Chilas. Earlier that year, assailants had also blown up two schools.

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