A Brazilian judge has ordered for the IMMEDIATE seizure of Ryan Lochte's passport -- claiming he may have lied about a robbery incident in Rio ... but the swimmer is already back in the U.S.
Brazilian authorities have issued a statement to TMZ Sports saying, "Judge Keyla Blanc De cnop, the Special Court of the Fan and Major Events, ordered the dispatch of search warrants and seizure of passports of American swimmers Ryan Lochte and James Feigen."
"With this, they are prohibited from leaving the country."
Lochte and Feigen had claimed they were together when their taxi cab was stopped and the swimmer were robbed by people posing as cops.