Twitter says it will hide tweets by world leaders and politicians that break its rules but have been left online "in the public interest".
Tweets from prominent government officials that break the platform's rules but have been left online will be hidden behind a notice.
The company accepted it had not clearly communicated many of the decisions it had made in the past.
But the new notice will only be applied to tweets sent after 27 June.
Twitter's critics say the platform does not enforce its rules evenly, allowing politicians to break its rules on abuse, harassment and incitement.
In the past, Twitter has defended some of its decisions by saying the tweets in question were "newsworthy".
For example, in September 2017 the company said it had decided to leave a controversial tweet by US President Donald Trump online.
In the tweet, Mr Trump said: "Just heard Foreign Minister of North Korea speak at UN. If he echoes thoughts of Little Rocket Man, they won't be around much longer!"
Many people interpreted the message as a threat to North Korea.
Although Twitter decided the post was newsworthy, there was no indication of this on the Twitter app or website.
Twitter did not say whether any particular politician had inspired the change to its rules.
Tweets placed behind the new notice will no longer appear in search results and will not be promoted by the platform's algorithms.
The new policy will only apply to people who:
- are or represent a government official, are running for government or are being considered for a position
- have more than 100,000 followers
- have a verified Twitter account
However, Twitter said in some cases - such as direct and immediate threats of violence - the tweets would still be removed.
The company said most users were "unlikely to encounter" the new notice often.
"This is a step, although a small step, in the right direction," said Dr Zoetanya Sujon from the London College of Communication.
"Of course, it doesn't stop soft racism or active political disinformation. And it will not have any visible impact on Twitter's harassment problem.
"Let's hope it can spark much better practice around the regulation of disinformation, hate speech, and incitement in political and public discussion on Twitter."
However, the platform is likely to face accusations of censorship when it places the first politician's tweet behind its new notice.
The company said old tweets would not be hidden behind the notice, and it could not predict when the new tool would first be used.