Twitter has retained the U.S. law firm Wachtell, Lipton, Rosen & Katz LLP as it prepares to sue Elon Musk and force him to finish the $44 billion acquisition of the social media business, according to sources with knowledge of the situation.

Musk, the CEO of Tesla, terminated the agreement on Friday, citing Twitter's failure to give information about false accounts on the network. In response, Twitter's chairman, Bret Taylor, threatened legal action.

According to sources with knowledge of the subject, Twitter plans to file a lawsuit in Delaware early this week.

Outside of work hours, Twitter declined to comment, and the legal firm did not immediately respond to Reuters' request for comment.

Wachtell, Lipton, Rosen & Katz was one of Musk's legal counsels for his 2018 plan to take Tesla private. Musk tweeted that he had "secured funding" for a $72 billion agreement to take Tesla private, but he did not make a bid.

Musk and Tesla each paid $20 million in civil fines, and Musk resigned as chairman of Tesla to settle Securities and Exchange Commission allegations that he deceived investors.

Twitter's legal team members are Simpson Thacher & Bartlett LLP and Wilson Sonsini Goodrich & Rosati.