Twitter Inc has dismissed Elon Musk's claims in a Delaware court filing that he was hoodwinked into signing the deal to buy the social media company, saying that it was "implausible and contrary to fact".
Musk made the claims in a countersuit that he filed under seal last Friday, which was made public on Thursday.
"According to Musk, he -- the billionaire founder of multiple companies, advised by Wall Street bankers and lawyers -- was hoodwinked by Twitter into signing a $US44 billion ($A63 billion) merger agreement. That story is as implausible and contrary to fact as it sounds," the filing released by Twitter on Thursday said.
Twitter's filing is the latest salvo in what is building up to be a major legal showdown between the world's richest person and the social media giant.
The San Francisco-based company is pushing to resolve months of uncertainty over its fate as Musk tries to walk away from the deal for what he says is Twitter's misrepresentation of fake accounts.
Musk, the chief executive of electric car company Tesla Inc , offered to buy Twitter for $US54.20 ($A77.76) per share in April, saying he believed in its potential as a global platform for free speech.
But he soured on Twitter as its stock price lagged his takeover bid, and began expressing scepticism that bot and spam accounts represented less than 5 per cent of users.
Musk sought to back out on July 8 without paying a $US1 billion ($A1.4 billion) breakup fee, citing Twitter's failure to provide details on bot and spam accounts. Twitter sued him four days later.
The company accused Musk of sabotaging the deal because it no longer served his interests, and casting a pall that disrupted its work and hurt shareholders.
An October 17 trial is scheduled.
Earlier this week, Twitter issued dozens of subpoenas to banks, investors and law firms that backed Musk's takeover bid, while Musk issued subpoenas to Twitter's advisers at Goldman Sachs and JP Morgan over their work.
Legal experts have said Twitter's requests suggested the company wanted to know why Musk turned against it, or whether he reneged on his obligation to obtain sufficient financing.
A representative for Musk did not immediately respond to a request for comment.