Elon Musk and Twitter fired shots at each other on Tuesday in the latest round of legal filings regarding the billionaire's efforts to cancel his offer to buy the social media platform.

Musk submitted additional papers to terminate his agreement to purchase Twitter, with Twitter responding that his attempt to back out of the deal is invalid and wrong.

In a filing with the Securities and Exchange Commission, Musk said his legal team informed Twitter of "additional grounds" to terminate the deal beyond those stated in the original termination notice issued in July.

Zatko, who served as Twitter's head of security until he was dismissed earlier this year, alleged in his complaint to U.S. officials that the company misled regulators about weak cybersecurity defenses and its neglect in attempting to eradicate fake accounts spreading misinformation.

The letter, addressed to Twitter's chief legal officer Vijaya Gadde, said Zatko's allegations provide additional reasons to terminate the deal if the July termination notice is deemed "invalid for any reason."

While billionaire Musk spent months claiming that the company he agreed to acquire was undervalued due to fake accounts and spam, meaning he is not obligated to execute the $44 billion deal. Musk's decision to withdraw from the deal paves the way for a high-stakes legal battle in the coming October.

In a separate filing to the Securities and Exchange Commission, Twitter responded to what it called Musk's latest "alleged termination," saying it "relies solely on statements made by a third party, full of contradictions and inaccuracies and lacking important context."

The company pledged to proceed with the sale at the agreed price with Musk despite all the allegations.