Brazilian Supreme Court Justice Alexandre de Moraes has opened an inquiry into Elon Musk for obstruction of justice involving social media company X, according to a court document.

Musk is challenging a decision by Moraes on Sunday, ordering his social media platform X to block certain accounts.

Musk earlier on Sunday posted that X would lift the restrictions because they were unconstitutional.

In his decision, Moraes said, "X shall refrain from disobeying any court order already issued, including performing any profile reactivation that has been blocked by this Supreme Court."

If X fails to comply with the order to block certain accounts the company will be fined 100,000 reais ($19,740) per day, the judge said.