Tesla's Chief Executive Officer Elon Musk announced the termination of a $44 billion deal with Twitter Inc, accusing the social media outlet of failing to provide information about fake accounts.

Shares of Twitter fell 6% in extended trading.

In a filing, Musk's lawyers said Twitter had failed or refused to respond to multiple requests for information on fake or spam accounts on the platform, which is fundamental to the company's business performance.

Musk had threatened to halt the deal unless the company showed proof that spam and bot accounts were fewer than 5% of users who see advertising on the social media service.

Last month, Twitter allowed Musk access to its "firehose," a repository of raw data on hundreds of millions of daily tweets.

Twitter did not immediately respond to a Reuters request for comment.

In a letter to the Securities and Exchange Commission, Musk said Twitter has "not complied with its contractual obligations" surrounding the deal, namely giving Musk enough information to "make an independent assessment of the prevalence of fake or spam accounts on Twitter's platform."

Musk's flirtation with buying Twitter appeared to begin in late March. That's when Twitter said he contacted members of its board - including co-founder Jack Dorsey - and told them he was buying up shares of the company and interested in either joining the board, taking Twitter private, or starting a competitor. Then, on April 4, he revealed in a regulatory filing that he had become the company's largest shareholder after acquiring a 9% stake worth about $3 billion.

At first, Twitter offered Musk a seat on its board. But six days later, Twitter CEO Parag Agrawal tweeted that Musk will not be joining the board after all. His bid to buy the company came together quickly after that.

Musk had agreed to buy Twitter for $54.20 per share, inserting a "420" marijuana reference into his offer price. He sold roughly $8.5 billion worth of shares in Tesla to help fund the purchase, then strengthened his commitments of more than $7 billion from a diverse group of investors including Silicon Valley heavy hitters like Oracle co-founder Larry Ellison.

Inside Twitter, Musk's offer was met with confusion and falling morale, especially after Musk publicly criticized one of Twitter's top lawyers involved in content-moderation decisions.

As Twitter executives prepared for the deal to move forward, the company instituted a hiring freeze, halted discretionary spending and fired two top managers. The San Francisco company has also been laying off staff, most recently part of its talent acquisition team.