Threads, which is a text-based platform that is similar to Twitter, has already passed 30 million sign-ups since its debut yesterday evening. Shortly after the platform launched, a lawyer for Twitter, Alex Spiro, sent a letter to Meta CEO Mark Zuckerberg accusing the social media giant of engaging in unlawful misappropriation of Twitter’s trade secrets and other intellectual property.

“Twitter intends to strictly enforce its intellectual property rights, and demands that Meta take immediate steps to stop using any Twitter trade secrets or other highly confidential information,” Spiro wrote in the letter, which Semafor shared online. “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.”

Spiro went on to accuse Meta of hiring “dozens” of former Twitter employees who “had and continue to have access to Twitter’s trade secrets” and other confidential information. The letter alleges these employees were then assigned to develop a copycat app using Twitter’s “trade secrets and other intellectual property in order to accelerate the development of Meta’s competing app, in violation of both state and federal law as well as those employees’ ongoing obligations to Twitter.”

Meta’s communications director Andy Stone responded to Twitter’s letter in a post on Threads, stating, “To be clear: No one on the Threads engineering team is a former Twitter employee — that’s just not a thing.”

Threads is one of many Twitter competitors that have gained traction since Elon Musk took over the reigns at Twitter last year. However, this latest development indicates that Threads is the most notable rival, given Twitter’s quick action against the platform.

Musk has stayed silent on the launch of Threads up until now, as the Tesla CEO backed the claims in Spiro’s letter in a tweet, stating that “Competition is fine, cheating is not.”

In addition, Twitter CEO Linda Yaccarino threw shade at the new platform earlier today. In a tweet, Yaccarino wrote that Twitter “is often imitated — but the Twitter community can never be duplicated.”

Zuckerberg posted a tweet for the first time in a decade yesterday moments after Threads launched. The Meta CEO posted a Spider-Man meme that poked fun at the fact that Threads resembles Twitter to some degree.

With Twitter making continuous questionable decisions, there’s a massive appetite for a replacement. Mastodon and Bluesky have both garnered notable buzz, but neither have seen as quick of an adoption rate as Threads has.

At launch, Threads is available on iOS and Android in 100 countries, though not in the EU, reportedly due to concerns around adhering to local data privacy regulations. To access Threads, users first need to authenticate using their current Instagram login credentials. The app will then populate with their existing account details, like name, username, photo, and followers.