Washington - Twitter is citing "newsworthiness" and the public interest as reasons why it didn't remove President Donald Trump's declaration in a tweet that North Korean leaders may not "be around much longer."Trump tweeted Saturday: "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!"Twitter's rules state users "may not make threats of violence or promote violence, including threatening or promoting terrorism."Twitter responded to questions about the policy on Monday, saying in a series of messages on its public policy account that "newsworthiness" is one of the factors it considers in determining if a tweet breaks the platform's rules. It says the policy has been internal, but its public-facing rules will be updated to reflect it.