Malala Yousufzai and her father Ziauddin have become the first signatories of a petition calling for better protection for teachers and students in Pakistan.
The petition, addressed to the president of Pakistan, is in response to the killing of a teacher on her way to work at a girls' school in Pakistan's north-west tribal region on Tuesday.
The killing took place not far from where Malala herself was shot in the head as she returned from school in October 2012.
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The 36-year-old has not been seen or heard from since Thursday evening.
Sophie Neville, cast as Titty as a young child in the 1974 classic Swallows and Amazons, is advising its modern-day adaptation.
At least two people are feared dead in the attack which is the latest on medical facilities in the war-torn country.