Twitter is introducing new rules around hate symbols, sexual advances and violent groups, in an effort to counter perceptions that the social network is not doing enough to protect those who feel silenced on the site.

The company was planning to announce the new rules later on this week, but they leaked in an email to Wired magazine, which published the changes on Tuesday.

“We hope our approach and upcoming changes, as well as our collaboration with the Trust and Safety Council, show how seriously we are rethinking our rules and how quickly we’re moving to update our policies and how we enforce them,” a Twitter spokesperson said. The company had launched its Trust and Safety Council in February 2016, with membership of more than 40 organisations including the US Anti-Defamation League, Samaritans and the Internet Watch Foundation to help Twitter “more efficiently and quickly” canvass for opinion from experts.

The changes come a few days after Twitter’s chief executive, Jack Dorsey, acknowledged the company’s failings in a short series of tweets posted on the day of the #womenboycotttwitter protest. The protest was sparked by the company locking the account of actress Rose McGowan, after she sent a series of tweets attacking those she claimed had enabled the abuse of Hollywood mega-producer Harvey Weinstein.

“We see voices being silenced on Twitter every day. We’ve been working to counteract this for the past 2 years. We prioritized this in 2016. We updated our policies and increased the size of our teams. It wasn’t enough,” Dorsey wrote.

“In 2017 we made it our top priority and made a lot of progress. Today we saw voices silencing themselves and voices speaking out because we’re *still* not doing enough.”

As part of the changes, Twitter’s rules on non-consensual nudity (sometimes called “revenge porn”) and unwanted sexual advances have been strengthened, with the former expanding to include imagery that isn’t explicitly nude, such as “upskirt” pictures, and the latter ban being extended to cover bystander reports, rather than only being actionable if the target complains. Users who are the original posters of non-consensual nudity, or those who share it explicitly to harass someone, will also receive an immediate permanent ban, rather than a temporary account lock for first offenders.

The raft of rules concerning hate symbols and violent groups are completely new, although the email acknowledges that their “exact scope” is still being determined. Hateful imagery and hate symbols will now be treated as “sensitive media”, similar to how pornography is already flagged and blockable, while the company says it will “take enforcement action against organisations that use violence as a means to advance their cause”.

Twitter will also begin to take action against tweets that glorify or condones violence, as well as simple threats. “We realize that a more aggressive policy and enforcement approach will result in the removal of more content from our service. We are comfortable making this decision,” the leaked email says.

The company’s proposed changes have already been criticised as addressing the wrong problems, however. Brianna Wu, a US congressional candidate who made her name as an anti-harassment campaigner, told Dorsey that the changes “require trusting the reporting process. Your reporting outcomes are very uneven - I can report the same behavior one day and it’s acted on. The next day it’s not.

“Unless you are investing more in personnel and training staff in subjects they may not understand, this isn’t going to solve it.”

Uneven enforcement was ultimately the reason for the #womenboycotttwitter protest in the first place. McGowan’s account was locked, Twitter said, because one of her tweets contained an image private phone number. When Twitter cited this as the reason for McGowan’s suspension, others noted that they had reported similar tweets and seen no enforcement action taken.