The Department for Education (DfE) has urged schools to be vigilant in guarding against the dangers of female genital mutilation ahead of the summer holidays, known to be a particularly dangerous time for at-risk girls.

The department has sent out an email to all schools in England and Wales drawing attention to updated guidelines designed to keep girls safe before the start of the summer break, sometimes referred to as the "cutting season" for girls at risk of mutilation.

Michael Gove previously wrote to all headteachers advising them of the dangers of the practice, which involves the removal of a girl's outer sexual organs and can lead to lifelong trauma and physical complications, after a Guardian-backed campaign to raise awareness of the practice attracted more than 234,000 signatures on Change.org.

An estimated 66,000 women and girls in the UK have been victims of FGM, and as many as 24,000 girls under the age of 15 are believed to be at risk.

The campaign, led by 17-year-old student Fahma Mohamed, gained the support of the UN secretary general, Ban Ki-moon, and the Pakistani schoolgirl and education activist Malala Yousafzai. It also inspired the 24-year-old American mother-of-three Jaha Dukureh to launch a similar campaign in the US on Change.org, calling for the government to gather more information about the practice, which experts warn is happening to US citizens on American soil.

The DoE's email to schools states: "On 3 April 2014 the government published new statutory safeguarding guidance for all schools, Keeping Children Safe in Education. The guidance specifically addresses female genital mutilation (FGM) and provides a link to multi-agency guidelines on that issue."

The email goes on to urge teachers to "be vigilant, particularly in the summer term, as girls may be at risk during the summer holidays".

Efua Dorkenoo, the senior FGM advisor at Equality Now, welcomed the move but called for further action. "It is fantastic that the Department for Education has let teachers know that they should be alert to possible signs of FGM before the summer holidays," she said.

"However, teachers should be trained too on reporting and sharing information and on precise details of which warning signs to look out for, and they should be held accountable. It is also vital that young FGM survivors are given care and support."