Elon Musk says his deal to buy Twitter can't move forward unless the company shows public proof that less than five percent of the accounts on the social media platform are fake or spam.Musk made the comment in a reply to another user on Twitter early Tuesday. He spent much of the previous day in a back-and-forth with Twitter CEO Parag Agrawal, who posted a series of tweets explaining his company's effort to fight bots and how it has consistently estimated that less than five percent of Twitter accounts are fake.In his tweet Tuesday, Musk said that «Twenty percent fake/spam accounts, while four times what Twitter claims, could be much higher.