Online violence against female journalists is one of the most serious global threats to press freedom and has contributed to female reporters being murdered, a new global report has found.

Researchers behind the report called "The Chilling: Global trends in online violence against women journalists," interviewed over 1,000 female journalists in 15 countries, according to The Guardian.

Globally, the research found that almost three-quarters of the female journalists surveyed had experienced online violence in the course of their work.

Threats of physical violence, including death threats, were identified by 25 percent and sexual violence by 18 percent.

And 13 percent described threats of violence against those close to them, including children and infants.

Almost half – 48 percent – of the female journalists surveyed reported being harassed with unwanted private social media messages.

The authors of The Chilling are now calling for governments, news industry and the giant tech corporations, to do more to tackle what they say is "a crisis of online violence towards women journalists".

They are also urging social media companies to overhaul algorithms that drive hate against women, and for perpetrators of gender-based online violence to be de-platformed and penalised.

The report which is based on research by the International Centre for Journalists (ICFJ) and the University of Sheffield, illuminates the evolving challenges faced by female journalists. It calls out "the victim-blaming and slut-shaming that perpetuates sexist and misogynistic responses to offline violence against women in the online environment, where patriarchal norms are being aggressively reinforced."

Among the interviewees was award-winning investigative Guardian and Observer journalist Carole Cadwalladr. Cadwalladr had exposed how personal data belonging to millions of Facebook users was secretly collected by British consulting firm Cambridge Analytica, largely for political advertising.

The research team's analysis found that Cadwalladr was the target of 10,400 separate instances of obvious abuse during the time between December 2019 and January 2021.

It found that the abuse was highly gendered and designed to "humiliate, belittle and discredit" the journalist on both personal and professional levels.

Cadwalladr told researchers how "a few hundred years ago I would have been burned at the stake" and how she has now become a "national punching bag".

The report also maps the online-offline violence trajectory, showing how digital harassment and threats led to offline attacks. It highlights the murder of Mexican journalist María Elena Ferral, who had denounced online harassment from the son of a city mayor before she was killed.

Prof Kalina Bontcheva, senior researcher in the UK arm of the study, said: "Our report has found that we are now at a crisis point in the level of violence being directed towards women journalists.

"The vast majority who took part in the study had suffered from online violence, so UK policymakers need to take urgent action now in order to protect the lives of those who are doing such an important job in society."

Bontcheva called for the much-delayed online safety bill to be passed urgently as the report laid out a series of other recommendations.

The UK arm of the research found that online violence against female journalists is frequently associated with polarising political debates – such as that surrounding Brexit – and that the Covid pandemic has worsened the situation.