The FBI said Sunday it had alerted Philadelphia-area colleges and universities to a social media post threatening a violent attack on an unspecified campus Monday afternoon. 

The posting, on the anonymous message board 4chan, warned that "a fellow robot will take up arms against a university near Philadelphia. His cries will be heard, his victims will cower in fear, and the strength of the Union will decay a little more."

The posting went onto say that the attack would take place at 2 p.m. ET Monday and warned "If you are in that area, you are encouraged to stay home and watch the news as the chaos unfolds."

The message echoed a post on the site made hours before 26-year-old Chris Harper Mercer killed nine people at Umpqua Community College in Roseburg, Oregon Thursday. That posting said, "Some of you guys are all right [sic]. Don't go to school tomorrow if you are in the northwest." The FBI was investigating whether Mercer wrote the post. 

The FBI told Fox News it had notified area schools of the threat "out of an abundance of caution," and added "We encourage students, faculty, and employees at area colleges and universities to follow the guidance of their campus security officials."

WTXF reported that schools in and around the city, including Temple University, Drexel University, suburban Villanova University, and the University of Delaware will add extra patrols by campus police on Monday. The report said police and other security officials have been briefed on needing to report suspicious people or packages. There was no word that any university would close, suspend or otherwise alter operations Monday.

Fox News' Matt Dean, Rick Leventhal, and the Associated Press contributed to this report.

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