Virginia Tech officials urged calm Wednesday amidst news that e-mails and Internet postings originating in Italy contained threats of an attack on campus today.

Tech police, Virginia State Police and the FBI are working on the case, and Tech police have said that the threats are not believed to be credible.

The case dates to October, when a person or people using the screen name "NextKillerVirgTech" posted threats on the video-sharing Web site YouTube.com.

At least four Tech students interviewed by television reporters about those postings have since received unsettling e-mails alleged to be connected to the October incident.

Most of the messages have referred in some way to the April 16, 2007, shootings or shooter Seung-Hui Cho.

More recently, messages have warned that some kind of attack would occur today.

"While we take all threats seriously ... law enforcement authorities do not believe these communications represent a credible threat," Tech President Charles Steger wrote in an e-mail to the campus community Wednesday.

"Given all that this university has endured, I can understand how this can be very upsetting to the university community," he wrote.

"People are linking local events, such as alleged break-ins, with these threatening posts and e-mails, which are not borne out by the facts. All the indicators reviewed by law enforcement do not point to an immediate threat," the e-mail stated.

The university is scheduled to be open as normal today with an increased police presence.

Anyone receiving threatening Internet messages is asked to refrain from responding, save the messages and contact Virginia Tech police at 231-6411.