Virginia Tech is urging calm as e-mails and Internet postings originating in Italy threaten another attack on campus.

Though police do not believe the threats are credible, President Charles Steger said in an e-mail to faculty and students Wednesday that classes will be held Thursday with additional security across campus.

Given the public concern, Steger said an overabundance of caution is appropriate.

Authorities investigated similar threats earlier this month and in October and believe the new posts are from the same person.

Virginia Tech was the scene of the worst mass shooting in modern U.S. history in April 2007. Student Seung-Hui Cho killed 32 people on campus, then committed suicide.

Virginia State Police and the FBI are assisting in the investigation.

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