Nearly three-quarters of female journalists say they have been victims of harassment online and for 20 percent this has transferred into offline attacks, according to a UNESCO study published Friday.
The violence ranged from abusive language (49 percent) to threats of physical violence (25 percent) and sexual assault (18 percent).
Also included were threats to damage their professional reputations, digital security attacks and the use of manipulated images.
"These methods of attack are growing more sophisticated and evolving with technology such as Artificial Intelligence," said the report, based on a survey of 901 journalists across 125 countries.
"Many women journalists who participated in this survey said that they had been targeted as part of an organised digital disinformation campaign," it said.
While 64 percent of white female journalists reported online abuse, this rose to 81 percent for black, 81 percent for indigenous and 88 percent for Jewish women.
Stories about gender were most likely to trigger abuse, and lesbian or bisexual women were more likely to experience harassment than heterosexual women, the study found.
Many women resorted to self-censorship because they felt poorly protected by their companies, the report added.
"Many media employers still appear reluctant to take online violence seriously, in alignment with the evident failure of the internet communications companies -- whose platforms and apps facilitate much of the harassment, intimidation, and abuse targeting women journalists -- to take effective action," the study said.
It called for stronger legislation against online abuse, an end to attacks against female journalists by politicians and stronger support from employers and internet firms for their female staff.