Twitter owner Elon Musk is threatening to sue Mark Zuckerberg for copyright theft after the launch of his lib-friendly Twitter clone, Threads. 

A lawyer for Musk, Alex Spiro, accused Zuckerberg of poaching Twitter's employees in order to steal its trade secrets, calling the alleged conduct "systematic, willful, and unlawful."

The warning suggests that Twitter views Threads as a threat. The app, which is linked with social media heavyweight Instagram, gained 30 million users within a day of launching this week - making it the most rapidly downloaded app in history.

The splashy launch has titillated the left, which has embraced Threads as a less combative (that is, more controlled) alternative with the potential to replace Twitter.

Musk threatens lawsuit

It certainly appears to be the first serious challenger, eclipsing other sites that libs have fled to since Musk's takeover, like Mastodon. Libs have complained about Twitter becoming "toxic" under Musk, a self-described free speech advocate.

Musk registered his displeasure with the Threads buzz in a tweet.

"Competition is fine, cheating is not," Musk tweeted.

The letter from Musk's lawyer warned that Twitter will "strictly enforce its intellectual property rights" if Zuckerberg's company Meta does not desist from "using any Twitter trade secrets or other highly confidential information."

"Twitter reserves all rights, including, but not limited to, the right to seek both civil remedies and injunctive relief without further notice to prevent any further retention, disclosure, or use of its intellectual property by Meta."

Twitter in turmoil

A spokesman for Meta, Andy Stone, denied the accusation that the company was using former Twitter employees. Musk famously purged 80 percent of Twitter's employees after buying the company.

"No one on the Threads engineering team is a former Twitter employee — that's just not a thing," he said.

Musk has struggled to keep Twitter profitable, with advertisers fleeing the platform over an alleged rise in so-called "hate speech."

Twitter's new CEO, Linda Yaccarino, is an advertising specialist. She dismissed the hype over Threads in a post, saying Twitter has often been imitated but "never duplicated."

Complaints with Twitter haven't only come from the left. Many users were blindsided last weekend when Twitter limited the number of posts users could read every day - Musk said the move was in response to "data scraping."