Meta, which launched Threads Wednesday and has logged more than 30 million sign ups, looks to take on Elon Musk's Twitter by taking advantage of Instagram's billions of users.

"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.

Spiro, in his letter, accused Meta of hiring former Twitter employees who "had and continue to have access to Twitter's trade secrets and other highly confidential information," the report said.

Since Musk's takeover of the social media platform, Twitter has seen competition from Mastodon and Bluesky among others. Threads' user interface, however, has a striking resemblance to the microblogging platform.

Still, Threads does not support keyword searches or direct messages.

Meta and Spiro did not immediately respond to Reuters requests for comment.