The shots were reported around 8 p.m. at Nassau Hall, The Star-Ledger of Newark reported. The building, which dates from 1756, houses the president's office and other administrative offices.
Nassau Hall was cordoned off and evacuated, officials said. Students at a lecture in a nearby building were evacuated to the basement, WCAU-TV in Philadelphia reported.
By 11 p.m., university and Princeton police announced that the report appeared to be unfounded, KYW-TV in Philadelphia said.
The university sent a Twitter notice to students, faculty and staff at 8:45 p.m. saying: "Public safety has received a report of gunshots at Nassau Hall. Princeton Police responded; no one hurt. DPS says avoid area."
Princeton is normally a quiet college town with the university campus on one side of Nassau Street and the business district on the other.
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