The Department for Education has come under growing pressure to write to teachers informing them of the horrors of female genital mutilation, after a petition urging Michael Gove to intervene passed 100,000 signatures just 24 hours after it was put online.

The End FGM campaign, supported by the Guardian, saw people sign up at the rate of two a second to a document that asked the education secretary to write to all headteachers to inform children and parents about the practice.

Ministers held a cross-government summit on Thursday to announce a series of measures to tackle FGM, although they fell short of meeting the campaign's key demand. Government figures say 20,000 British girls are thought to be at risk of being cut every year. Fahma Mohamed, the 17-year-old face of the campaign, said she was overwhelmed at the support.

"It's absolutely amazing that we have already got so many signatures, it really shows how many people are behind this – we all believe the same thing, that education is key to ending FGM," she said. But she added: "Our goal is still to get [education secretary] Michael Gove to send a letter to all schools and reach out to teachers and parents. Today's announcement doesn't tell us what action they will really take. So we are going to keep on fighting."

On Thursday night, in response to the campaign, the Liberal Democrat president Tim Farron and party colleagues Julien Huppert and Greg Mulholland tabled an early day motion in parliament calling on the government and Department of Education to do everything in their power to stop the practice.

It states: "This house commends the work of 17-year-old student Fahma Mohamed, alongside the Guardian newspaper, to put a stop to this inhumane and unnecessary practice"

Norman Baker, the Home Office minister who is responsible for heading government policy on FGM, said he would be writing to Gove – whose voice was conspicuously absent from the day's announcements – to draw his attention to the Guardian's campaign.

"I'm delighted that a news organisation like the Guardian is running such a high-profile campaign, which will only add to efforts to defeat this appalling practice once and for all," Baker said.

Ministers from the departments of health, education and international development met to make a series of policy announcements, including:

• Mandatory collecting of data of victims in hospitals for the first time.

• A Home Office study into the prevalence of FGM.

• £250,000 of European money to promote a national NSPCC helpline and give training to frontline professionals.

• A redrafting of the existing safeguarding guidance note for schools, which will in future include guidance on FGM.

Speaking after the meeting, held on the United Nations day to mark zero tolerance of FGM, Baker said it marked a step change in government policy. "It sets out a real statement of intent, and a very strong message tying in every department into the campaign to end FGM. We are not saying that this will bring an end to FGM, but it is certainly a useful building block."

The international development minister, Lynne Featherstone, whose department announced £6.5m funding for a global FGM campaign, said: "We have come a long way, and we have much further to go, but everything is on track to end FGM within a generation."

It also emerged that the Crown Prosecution Service is investigating 10 cases of FGM in the UK, after setting up a network of 13 specialist prosecutors, and is "hopeful" that a case involving an adult woman will be brought to court within months.

"We are really stepping up what we are doing on FGM, as while there has been a lot of good practice being built up in London, this is not a problem unique to London," said Alison Saunders, director of public prosecutions.

She added: "We are still considering cases in London, each one bringing its own legal hurdle which we are trying to overcome. I am really hopeful we will have a case to progress through the courts in the next few months."

The shadow home secretary, Yvette Cooper, said the education department had to go further and offer both teachers and parents comprehensive training about FGM. "Getting the police and health professionals to do far more to help young women and prevent the mutilation is exactly right. But as the Guardian's campaign makes clear, education is crucial to ending this brutal crime in Britain.

"I hope Michael Gove will listen to the voices of the women and girls leading the Guardian campaign and take action."

Efua Dorkenoo, lead on FGM at campaign group Equality Now, who will advise on the revision of safeguarding guidance in schools, said the day was a watershed moment for campaigners, who finally felt that they were being listened to."We have been fighting for a long time for measures like these, and now we have got the government commitment across the board. It is the best news we have had on FGM for a long time," she said.

Debbie Ariyo, of the charity Afruca – which operates among the African diaspora in the UK and last year received funding to carry out FGM training in communities – said Fahma Mohamed would prove impossible for ministers across the government to ignore. "For many children from these communities the only time they can get support is at school. Teachers in schools need to know the dangers that these children are exposed to."

The Department for Education said safeguarding guidance for schools was being redrafted to ensure it was "clearer, simpler, and directs schools to the latest expert advice on issues such as FGM".

It added: "Female genital mutilation is unacceptable. It is child abuse and a criminal offence. It is an issue that schools should take very seriously. If a school is concerned that a pupil may be about to undergo FGM or may have been subject to it, they should contact their local authority safeguarding team immediately."