A 21-year-old Nevada man was arrested near the University of Washington, on Wednesday night, in connection with a truck, which was reported stolen recently from a residence in Butte, Mont., and was loaded with explosive devices, firearms and a bullet-proof vest, news reports said, citing police.

Law enforcement officials did not reveal the man's identity, but said he is not a student at the University of Washington, adding that they were investigating why he was in the area. NBC reported, citing prison records, that the arrested man was Justin Miles Jasper. 

“We have no idea what his intentions are,” University of Washington police chief John Vinson said, in a news conference, on Thursday afternoon, USA Today reported. “This is a very active investigation. We're trying to rule out everything at this point.”

Vinson said Seattle's police department and the FBI were involved in the investigation, and added that there were no reasons to believe the university was under any threat. 

University police said they first spotted the man sleeping in a truck, close to the campus late on Tuesday, but did not detect anything suspicious after running a check on the license plate. On Wednesday, police were alerted that a truck was reported stolen in Montana, which led to the man’s arrest at an address close to Seattle Children’s Hospital, NBC News reported.

The man, who was not formally charged with a crime, by Thursday night, was in custody at the King County Jail, news reports said, citing police sources.

Earlier, a U.S. national security official said, on Wednesday, that U.S. intelligence agencies had not detected any potential threats of militant attacks for the 4th of July holiday, Reuters reported.