Late on Saturday, Trump was urgently evacuated from the Washington Hilton Hotel during the White House Correspondents' Association gala after gunfire erupted inside the venue.
"He was armed with a shotgun, a handgun, and multiple knives. As he ran to that checkpoint, members of law enforcement from the United States Secret Service intercepted that individual," Carroll told a press conference.
The suspect appears to have acted alone, the police chief said. Preliminary details indicate he was a hotel guest, Carroll said. Washington police consider him the sole suspect in the enquiry, he noted.
US Attorney Jeanine Pirro said that the suspect will appear in court on Monday.
New York Post journalist Karol Markowicz reported the suspect is Cole Tomas Allen, a 31-year-old California resident from the city of Torrance, who works as a teacher.