ST. PAUL — A Minneapolis man charged with lying to the FBI during a terrorism investigation was ordered detained while his case is presented to a federal grand jury, after a magistrate judge said Monday that comments the 19-year-old posted on Twitter amounted to threats.

Hamza Ahmed was arrested last week as authorities are investigating people who have gone to Syria to fight with the Islamic State group. Court documents say Ahmed and three other men from Minnesota took a bus to New York City in November and tried to board flights overseas. All four were stopped.

Prosecutors argued that Ahmed should remain in custody. His attorney, JaneAnne Murray, sought his release and noted that prominent community members were in court to support Ahmed. Murray said comments her client made on Twitter were simply hubris.

U.S. Magistrate Judge Steven Rau disagreed.

“The tweets that you issued were beyond hubris, they were beyond youth,” Rau said. “They were threats.”