Twitter is failing to prevent online violence and abuse against women, creating a toxic environment for them, Amnesty International has claimed.

In a report published on Wednesday, the day that Twitter celebrates 12 years since the first tweet, Amnesty said the social network responded inconsistently when abuse was highlighted, even when it violated its own rules.

The human rights group accused Twitter of failing to respect women’s rights, with users in the dark as to how it interpreted and enforced its policies intended to prevent such toxic content. The result, Amnesty said, was death threats, rape threats and racist, transphobic and homophobic abuse aimed at women.

A survey of 1,100 British women carried out for the report found that just 9% thought Twitter was doing enough to stop violence and abuse against women, while 78% did not feel it was a place where they could share their opinion without receiving such vitriol.

Kate Allen, director of Amnesty International UK, said Twitter had become a “toxic place for women”. She said: “For far too long Twitter has been a space where women can too easily be confronted with death or rape threats, and where their genders, ethnicities and sexual orientations are under attack.

“The trolls are currently winning, because despite repeated promises, Twitter is failing to do enough to stop them. Twitter must take concrete steps to address and prevent violence and abuse against women on its platform, otherwise its claim to be on women’s side is meaningless.”

The report was based on interviews with more than 80 women, including politicians, journalists, and regular users in the UK and USA. While it found that public figures were often targets, others also experienced abuse – particularly if they spoke out about sexism or used campaign hashtags.

Amnesty said that while movements such as #MeToo on social media can be empowering, participants often faced a backlash.

Amnesty documented how women from ethnic or religious minorities, LGBTI women, non-binary individuals and those with disabilities were targeted with specific abuse against their identities. It said this could have the effect of “driving already marginalised voices further out of public conversations”.

Twitter said it disagreed with Amnesty’s findings, pleading that it “cannot delete hatred and prejudice from society”. It said it had made more than 30 changes to its platform in the past 16 months to improve safety, including increasing the instances of action it takes on abusive tweets.