Youngest ever Nobel Laureate and education activist Malala Yousafzai has strongly condemned the burning down of 12 schools, half of them all-girls', in Pakistan, saying the "extremists" have shown that a "girl with a book" frightens them the most.

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