Twitter on Monday faced a temporary boycott by some critics in Britain and a backlash from the government over its handling of a series of anti-Semitic posts by a high-profile rapper.
The social media giant, along with photo sharing site Instagram, on Friday banned grime artist Wiley from their platforms for seven days after he posted messages described as "abhorrent" by interior minister Priti Patel.
But some see the punishments as too soft and that the US companies took too long to remove the messages, prompting politicians, celebrities and other high-profile figures to launch a 48-hour Twitter boycott from Monday.
Patel has written to the firms asking why some of Wiley's posts were visible for more than 12 hours before being removed, and the government has said it expects a full response.
"The message is clear: Twitter needs to do better on this," Prime Minister Boris Johnson's official spokesman told reporters on Monday.
"Social media companies need to go much further and faster in removing hateful content such as this."
Police are now investigating the comments made on the Instagram and Twitter accounts of Wiley, who is considered a pioneer of the UK's popular grime music scene.
Britain's Chief Rabbi Ephraim Mirvis on Monday accused the two platforms of lacking "responsible leadership" in their response to the posts.
"This cannot be allowed to stand. Your inaction amounts to complicity," he said in letters sent to the heads of both firms.
Lisa Nandy, the main opposition Labour Party's foreign affairs spokeswoman, businessman Alan Sugar and television presenter Rachel Riley were among those to join the two-day boycott of Twitter.
Johnson's spokesman said he would continue to use the site for "important public health messages".