Twitter, facing pressure for not doing enough to curb abusive behavior on its platform, said on Tuesday it would upgrade some features to better combat cyber-bullying.

The company said it would expand the "mute" option to allow users to block tweets based on keywords, phrases and the content of conversations from a user's notifications.

The "mute" option currently allows users to block tweets from accounts.

The change will be rolled out to all users in the coming days, Twitter said in a blog post.

Twitter, which has struggled to strike a balance between free expression and blocking violent and hateful speech, has come under increasing criticism following complaints from users that they have been the target of abuse.

In July, Twitter permanently banned some user accounts for harassment after Ghostbusters actor Leslie Jones left the site, saying she had faced severe harassment.

Twitter said it would provide "a more direct way" for users to flag abusive content, but didn't give details.

The company also said it had improved internal controls to deal more effectively with abusive conduct reported by users.