(Reuters) - The U.S. Securities and Exchange Commission (SEC) has threatened to sue non-fungible tokens (NFTs) marketplace OpenSea, its CEO said in a post on social media platform X on Wednesday.

"OpenSea has received a Wells notice from the SEC threatening to sue us because they believe NFTs on our platform are securities," said OpenSea Co-founder and CEO Devin Finzer.

A Wells notice is a formal declaration that SEC staff intend to recommend an enforcement action.

The SEC does not comment on the existence or nonexistence of a possible investigation, a spokesperson for the securities regulator said in an emailed statement to Reuters.

The SEC and the crypto industry have locked horns in recent years over their divergent views on whether crypto assets classify as securities and should be regulated similarly.

"We're shocked the SEC would make such a sweeping move against creators and artists. But we're ready to stand up and fight," Finzer added.

Crypto companies have accused the regulator of overreach and violating its jurisdiction, while the SEC has alleged the industry is flouting securities laws that are designed to protect investors and other market participants.

Prominent crypto firms, including exchange Coinbase and retail trading app Robinhood, have repeatedly called for clearer regulation and new laws to accommodate the fast-growing sector.

An NFT is a digital asset that exists on a blockchain, which serves as a public ledger, allowing anyone to verify the asset's authenticity and ownership. NFTs have a unique digital signature and cannot be reproduced.

(Reporting by Manya Saini in Bengaluru; Additional reporting by Jaiveer Singh Shekhawat; Editing by Vijay Kishore)