The campus of Princeton University is reopen following an evacuation prompted by a bomb threat called in this morning around for 'multiple unspecified campus buildings."

FitzRandolph gate at Princeton re-opened after bomb search (Twitter)

7,000 students and staff were ordered to leave campus after the threat was received via phone according to a post to the University website.

No explosive devices were found.

"Please evacuate the campus and all University offices immediately and go home unless otherwise directed by your supervisor," read this morning's message, and "Do not return to campus for any reason until advised otherwise."

The threat came from a "known caller" according to WPVI TV.

Princeton High School was also in a "closed campus" status according to the school principal's Twitter feed as displayed on the Princeton Public School website.

6:25 p.m. - Princeton's campus is re-opened as the search of campus is complete. No explosive devices were found.Check with event organizers regarding the status of Tuesday evening activities.

Fire and poilice personnel on Princeton campus (WCAU TV)

Among the agencies assisting with today's evacuation: Princeton Police Department, Princeton First Aid and Rescue Squad, Mercer County Sheriff's Department and Prosecutor's Office, Monmouth County K-9 unit, New Jersey State Police, New Jersey Transit Police, the Federal Bureau of Investigation and federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

3:47 p.m. The search continues on campus. The University notes that there were several bomb threats made around the country including Richmond Airport and the University of New Hampshire. Princeton hopes to reopen campus this evening

TigerTransit service has been suspended until Wednesday morning.

3:19 p.m. - As the building-by-building search continues ABC News reports a "suspicious package" was found on campus during the morning's initial search. Planet Princeton reports it was a crock pot left behind in a unit at Lawrence Apartments when someone moved out.

1:30 p.m. - Bomb sniffing dogs are searching campus facilities according to an update on the Princeton website. The search will take several hours. "The University takes all threats to the safety and well being of our community members and visitors seriously and is fully cooperating with the ongoing investigation," reads the statement.

1:29 p.m. - Princeton Police say all closed roads have been reopened but ask drivers to avoid downtown Princeton

1:27 p.m. - The Daily Princetonian reports confusion on campus about where to evacuate because no alarms went off and dependent on text messages, email and phone calls.

12:44 p.m. - NJ Transit says the Princeton Shuttle (Dinky) service has been restored.

12:20 p.m. - Princeton University will offer an update at 1:30 p.m.

12:11 p.m. A tweet from Princeton University says "university, local, state, federal authorities (are) investigating" the threat.

11:52 a.m.: NJ Transit says the Princeton Shuttle (Dinky) service is currently suspended in both directions due to the evacuation.

Princeton Police direct traffic during evacuation of Princeton University (Brian McCarthy, On Scene News)

11: 44 a.m. Roads around campus are described as being gridlocked around campus. Harrison Street  leading towards Route 1 and Nassau Street are both jammed with traffic. No traffic is being allowed into downtown Princeton according to Princeton Police who recommend that Route 206 in both directions and Route 27 are the best ways to leave campus.

11:40 a.m. Those leaving campus can also go to Nassau Inn, Princeton Public Library and Princeton Arts Council building downtown according to a university tweet.

11:30 a.m.: The Fitz-Randolph gate onto campus has been closed.

Earlier Information:

University spokesman Dan Day says no classes are in session, though there are some summer programs on campus.

Princeton Police say they are assisting the Princeton Department. of Public Safety and are treating it as a "credible" threat "in the interest of public safety."

Princeton University evacuation tweets (Twitter)

Those without cars will be directed to an evacuation site.

Seton Hall was evacuated on May 30 for bomb threat that also said bombs were located at multple locations. Former Seton Hall student Dennis Mamrosz of Yonkers was arrested on third-degree terrorist threats.